1.8 needs a little more pep

[FadedBlue]

Hey guys brand new DSM owner here, its a 94 Eclipse base 1.8 just bought it today and looking to learn a bit more about it. I plan on changing the oil tomorrow along with the fuel filter, which it needs bad, from the maintenance records the oil was last changed around 227,000 miles its a little over 230,000 now so I think its due for that. Anyways before I change the oil I was thinking about running some seafoam through to clean it out I have seen it done on other cars is it the same with DSMs?
When the car is in neutral the oil light comes on and the oil pressure gauge is at the bottom what would the cause of that be?
Are there any aftermarket temp gauges that I could use since the stock one isn't working properly.
On to my main point this car really needs some more power, I don't need it running 10s or anything like that but I at least need some get up and go power so I'm assuming the basic bolt on mods such as intake, exhaust, and throttle bodies will help me out?
Finally what can fit in the rear hatch? I have a set of orion subs from my old neon that I plan on putting in I haven't checked to see if they fit yet, they are 12" XTRs, also what size are the stock speakers? I have pioneer 6x9s and Kicker 6" door speakers also from my old neon.

 

[91stocker]

I wouldn't even bother honestly. A friend of mine ran his 1.8 at the track and ran high 18's. No joke. That was on a freshly rebuilt motor too.

 

[Mischif]

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The screw im pointing to is the base idle screw, and the screw the flat head is pointing at is the idle speed motor adjusting screw.

 

[FadedBlue]

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The screw im pointing to is the base idle screw, and the screw the flat head is pointing at is the idle speed motor adjusting screw.

Ok thanks I'll adjust that later and update with results

 

[Diamond Star Werks]

Maybe its just me, but i dont ever like to see it idle above 1200 even during a cold start. Even above 1000 it annoys me.

it is just you. Ecu runs richer and a higher idle steps the colder the temp. It was made to idle up when cold. Then slowly lower as out warms up.

 

[FadedBlue]

it is just you. Ecu runs richer and a higher idle steps the colder the temp. It was made to idle up when cold. Then slowly lower as out warms up.

My idle just spikes then drops back down when cold its not gradual at all

I plan on ordering the oil pump tomorrow, and possibly doing the balance shaft eliminator is this write up I found good for the 1.8? Balance Shaft Eliminator Kit Install I shouldn't have to remove the timing belt right? I would prefer not to do that

 

[DSM1G90]

You leave that screw alone !

That adjusts the TPS with the butterfly and that can really screw up your idle mixture with the ECU!. The idle speed screw is the one with the spring where your finger is at in the pict.

But, before messing with any idle speed, check your timing..which is the same as with the 4G63: Ground the ECU terminal and base timing at 5* BTDC.

Go out to the yards and find a CYCLONE head - a 12V head that instead of using hydraulics for lash adjustments, the adjustments are adjustable with a feeler gauge (.010 exh and .008 int). The third valve, the size of a penny nail was for the MCA-JET jet air system to really mix the mixture before ignition.

This head does give a bit more bump for this 4G37 along with using NGK BPR6ES-11 at .044 inch gap.

 

[Doesnt start monthly]

Do not waste your time trying to make a 1.8 fast. Won't happen, I has a 94 1.8 with the auto km175. Rebuilt both the trans and motor and had over 3,000 into it. Was great for DD but I think a paper weight was faster then it. Also moding at 230k probably not the best choice if the car hasn't been taken care, you'll probably end up with a paper weight.

 

[FadedBlue]

You leave that screw alone !

That adjusts the TPS with the butterfly and that can really screw up your idle mixture with the ECU!. The idle speed screw is the one with the spring where your finger is at in the pict.

But, before messing with any idle speed, check your timing..which is the same as with the 4G63: Ground the ECU terminal and base timing at 5* BTDC.

Go out to the yards and find a CYCLONE head - a 12V head that instead of using hydraulics for lash adjustments, the adjustments are adjustable with a feeler gauge (.010 exh and .008 int). The third valve, the size of a penny nail was for the MCA-JET jet air system to really mix the mixture before ignition.

This head does give a bit more bump for this 4G37 along with using NGK BPR6ES-11 at .044 inch gap.

Well the timing belt on it is less than a few weeks old. Here's the background on the car from what I know. It was originally bought in Virginia, went to Washington, then ended up in Michigan where I bought it. I'm the third owner, the guy I bought the car off of had it for about 3 weeks as a temporary thing because his was in the body shop for a while. When he bought it off the original owner it had a broken timing belt. He replaced the timing belt, plugs, and wires. That's all less than a month old. The valves don't seem bent because aside from the low idle and oil issue its been driving smooth. I'm changing the fuel filter tomorrow and from the maintenance records I got with the car it was recommended to be changed way back in 03 further looking at the records I see fuel system cleaning every now and then so I believe that the owner was just using temporary solutions instead of fixing a $20 problem, I only hope it hasn't partially clogged any of my injectors making it slower than it already is. In my spare time tomorrow I'm trading some games into gamestop for the extra cash I need to get the oil pump this is the one I'm buying seller has 100% feedback 89 94 Dodge Mitsubishi 1 8L SOHC 8V 4G37 Oil Pump | eBay I'm gonna get the one day shipping so I can have the car ready to go by friday. While I'm changing the fuel filter tomorrow I'll correct the idle issue this should also allow me to use the AC without the vibrations that was happening when I had it on idling at 500 but when I gave it gas the vibrations went away also should fix my oil light issue at idle I'm still replacing the pump though. Based on this info what do you guys think? I bought the car for 1100.


Also as a sidenote my Orion XTRs fit in the hatch without a problem, not yet hooked up though.

Ok have an update, I was looking more into my idle issue it was idling at about 700-800rpms when warm with no load on the motor but when I engaged the AC it would drop it down to 500, I shut the car off Unplugged the idle air control harness tightened up the idle control screw getting it idling to about 1200rpms I then shut the car down and plugged the harness back in. After this i started the car again and it was idling around 1000rpms with no load I again turned on the AC and it would still drop the idle down to 500 I believe that also turning the radio up would also drop the idle down I haven't yet checked that though. I did some research this seems to be my exact problem Mitsubishi Repair: Low idle and stalling, mitsubishi eclipse, electrical load but I'm confused as to what to do would I have to replace the idle air control valve, or the harness? Please help I need to get this issue corrected soon.

 

[Mischif]

Its pretty common for the IAC to go bad. Its common practice that once they go bad just to unbolt it from the throttle body and ziptie it out of the way somewhere leaving it plugged into the harness. You just use the main idle screw to set idle. With just manual idle controls whenever a load is applied to the engine it shouldn't drop more than 100-200rpms. So if your dropping 500rpms with the a/c on then that might mean your a/c compressor or tension pulley could be going bad. Causing an excess drag bogging the motor down more than it should.

Also the timing belt has to come off when you replace the oil pump. Its extremely easy to retime the engine so don't worry about it. Don't worry about the timing belt either, if its that new its fine to reuse it. Also since your going to have to take the oil pump off might as well do the balance shaft elimination. That will make timing the engine even easier as you dont have to worry about lining up the front shaft or the oil pump sprocket with the timing marks or making sure the rear shaft is in the correct phase.

 

[FadedBlue]

Its pretty common for the IAC to go bad. Its common practice that once they go bad just to unbolt it from the throttle body and ziptie it out of the way somewhere leaving it plugged into the harness. You just use the main idle screw to set idle. With just manual idle controls whenever a load is applied to the engine it shouldn't drop more than 100-200rpms. So if your dropping 500rpms with the a/c on then that might mean your a/c compressor or tension pulley could be going bad. Causing an excess drag bogging the motor down more than it should.

Also the timing belt has to come off when you replace the oil pump. Its extremely easy to retime the engine so don't worry about it. Don't worry about the timing belt either, if its that new its fine to reuse it. Also since your going to have to take the oil pump off might as well do the balance shaft elimination. That will make timing the engine even easier as you dont have to worry about lining up the front shaft or the oil pump sprocket with the timing marks or making sure the rear shaft is in the correct phase.

So I don't even need the IAC? I wish someone had told me this before I won't even bother with it now. Once I get the oil pump changed and it all put back together I'll unplug the IAC and do a manual idle to see if it fixes the problem or if it actually the compressor or pulley going bad. If its the tension pulley would hooking up my subs also cause an excess drag because the alternator would have to work harder? I'm waiting til after I get all the issues out of the way before hooking them up

 

[Mischif]

When i used to have subs, and at night with the lights turned on, my idle still only dropped 100-200rpms compared to during the day with no load on it. That was with a manual idle as well.

I also suppose it could also be the alternator starting to go, which is causing the bog at idle.

 

[Narish Do Urden]

Its pretty common for the IAC to go bad. Its common practice that once they go bad just to unbolt it from the throttle body and ziptie it out of the way somewhere leaving it plugged into the harness. You just use the main idle screw to set idle. With just manual idle controls whenever a load is applied to the engine it shouldn't drop more than 100-200rpms. So if your dropping 500rpms with the a/c on then that might mean your a/c compressor or tension pulley could be going bad. Causing an excess drag bogging the motor down more than it should.

Also the timing belt has to come off when you replace the oil pump. Its extremely easy to retime the engine so don't worry about it. Don't worry about the timing belt either, if its that new its fine to reuse it. Also since your going to have to take the oil pump off might as well do the balance shaft elimination. That will make timing the engine even easier as you dont have to worry about lining up the front shaft or the oil pump sprocket with the timing marks or making sure the rear shaft is in the correct phase.

+1 My IAC is messed up right now but this is the 4g63t 2.0, its pretty common on all though regaurdless

 

[FadedBlue]

+1 My IAC is messed up right now but this is the 4g63t 2.0, its pretty common on all though regaurdless

Well mine is the 1.8 4g37 but I do believe the IAC is the same on either one? I'm still gonna take it off. I hope this weather warms up soon I'm already not looking forward to putting the new oil pump in frozen parts will just make it worse

Also just thought of this while reading my haynes manual it says to take the timing belt off when I go to change the oil pump, I will have to re-time it right?

 

[DSM1G90]

Take the IAC off and goodbye in controlling idle when cold. Checked in the Temp Sensor if that needs to be replaced? Temp sensor tells the ECU what the temp of the coolant is. If sensors are bad, the ECU thinks the coolant temp is 77*, thus telling the injectors that a rich condition is not needed to get the motor started.

yep .. all belts are off when doing the pump change out (why are you changing out the pump? Them things never die..unless your pressure is low).

AC on a 4cyl just don't belong to each other since the compressor really pulls the load off the front pulley to run six pistons inside that compressor-three to pull the freon from the evaporator inside the car and the other three to push the freon back through the system. With AC on, the idle stop set opens up the throttle plate a bit to increase idle to compensate for compressor load.

Compressors can pull almost 15hp off the front end of the motor with no problems. This is why a lot of DSM owners remove the AC from their vehicles due to this condition .. and usually compressors almost pushing 20 yrs old are ready to give out - why they drag the motor down because they're ready to seize.

Have you done a compression check? 1993 motor could have tired compression rings where your loss of power is the results.

its a little over 230,000 now so I think its due for that

If my body had 230k on it, I'd be tired as well. "Dang!" I bet those compression rings are super tired - the whole motor is due for an overhaul with new bearings, head job and rings.

Also, you might have a plugged CAT, also do to the age which will also result in poor performance. To check a plugged CAT, is to drill a 1/8" hole at the entrance of the CAT where the EXH pipe goes in. If you suddenly pick up power, that CAT is just about, or all but plugged.

Lastly, if all is good, increase the exhaust pipe system to 3inch piping to allow the motor to breathe better. The 4G37 is a duable motor, but is horribly choked, mainly due to the exhaust system...along with the car is a heavy beast for such a small motor. Vehicle weighs in at almost 2600 lbs, making the motor slightly underpowered.

Mitsu should have placed the 4G63 SOHC in as the NT option and used the DOHC with as the turbo option instead of a small lawnmower motor for its base model. Motor doesn't even weigh 200 lbs where two guys can throw one in the trunk of a car-it's so little.

You must realize that 1.8L is really a small Cubic Centimeter motor, and back in 1980s when the 4G37 was introduced, that was the "motor of tomorrow" for Mitsu since it powered so many small Japanese vehicles-which were light and nimble thus making those cars really have some pep. The choice for Chrysler to use that motor in their DSM line was really a mistake, but was quick, and cheap since it was already available, why in 1995, they dropped the 4G37 for their own 420A NT motor for the next body style.

 

[FadedBlue]

Take the IAC off and goodbye in controlling idle when cold. Checked in the Temp Sensor if that needs to be replaced? Temp sensor tells the ECU what the temp of the coolant is. If sensors are bad, the ECU thinks the coolant temp is 77*, thus telling the injectors that a rich condition is not needed to get the motor started.

yep .. all belts are off when doing the pump change out (why are you changing out the pump? Them things never die..unless your pressure is low).

AC on a 4cyl just don't belong to each other since the compressor really pulls the load off the front pulley to run six pistons inside that compressor-three to pull the freon from the evaporator inside the car and the other three to push the freon back through the system. With AC on, the idle stop set opens up the throttle plate a bit to increase idle to compensate for compressor load.

Compressors can pull almost 15hp off the front end of the motor with no problems. This is why a lot of DSM owners remove the AC from their vehicles due to this condition .. and usually compressors almost pushing 20 yrs old are ready to give out - why they drag the motor down because they're ready to seize.

Have you done a compression check? 1993 motor could have tired compression rings where your loss of power is the results. If my body had 230k on it, I'd be tired as well. "Dang!" I bet those compression rings are super tired - the whole motor is due for an overhaul with new bearings, head job and rings.

Also, you might have a plugged CAT, also do to the age which will also result in poor performance. To check a plugged CAT, is to drill a 1/8" hole at the entrance of the CAT where the EXH pipe goes in. If you suddenly pick up power, that CAT is just about, or all but plugged.

Lastly, if all is good, increase the exhaust pipe system to 3inch piping to allow the motor to breathe better. The 4G37 is a duable motor, but is horribly choked, mainly due to the exhaust system...along with the car is a heavy beast for such a small motor. Vehicle weighs in at almost 2600 lbs, making the motor slightly underpowered.

Mitsu should have placed the 4G63 SOHC in as the NT option and used the DOHC with as the turbo option instead of a small lawnmower motor for its base model. Motor doesn't even weigh 200 lbs where two guys can throw one in the trunk of a car-it's so little.

You must realize that 1.8L is really a small Cubic Centimeter motor, and back in 1980s when the 4G37 was introduced, that was the "motor of tomorrow" for Mitsu since it powered so many small Japanese vehicles-which were light and nimble thus making those cars really have some pep. The choice for Chrysler to use that motor in their DSM line was really a mistake, but was quick, and cheap since it was already available, why in 1995, they dropped the 4G37 for their own 420A NT motor for the next body style.

My oil pressure is way low and at idle the oil light is on so I'm changing the pump. I'm just trying to get this car running normal til I get money to throw at it

Also is there anything I can do to make the car lighter? I can probably go pick up a compression tester later today while I'm working on the car.

 

[Mischif]

Have you done a compression check? 1993 motor could have tired compression rings where your loss of power is the results. If my body had 230k on it, I'd be tired as well. "Dang!" I bet those compression rings are super tired - the whole motor is due for an overhaul with new bearings, head job and rings.

A compression test would be a good idea to see exactly what shape the engine is in. However just because it has high mileage doesn't mean you should expect it to be worn. That all depends on how well it was maintained. I have a tad over 228k on mine and my compression is almost perfect still.

To the OP when you do your oil pump, since you have to drop the oil pan, give your rods a good hard shake from the end caps. If you dont feel any play in them at all then the bearings are still in good shape.

 

[FadedBlue]

A compression test would be a good idea to see exactly what shape the engine is in. However just because it has high mileage doesn't mean you should expect it to be worn. That all depends on how well it was maintained. I have a tad over 228k on mine and my compression is almost perfect still.

To the OP when you do your oil pump, since you have to drop the oil pan, give your rods a good hard shake from the end caps. If you dont feel any play in them at all then the bearings are still in good shape.

Thanks for the suggestion I'll remember to do that when I get to working on it, not having a heater for my garage is really slowing me down on it

 

[DSM1G90]

My oil pressure is way low and at idle the oil light is on so I'm changing the pump. I'm just trying to get this car running normal til I get money to throw at it

Ummm...hate to say it, but with a block with that many miles, no new oil pump will bring your pressure back to normal since the main connecting rod bearings are super tired and letting oil go past them-why you're losing oil pressure at idle. They can be tight as mischif mentions, but just worn enough to allow oil to flow past them.

If the oil gauge needle pegs at normal when the oil is cold, then falls to nothing when oil is hot, that's a definite sign that the main bearings are weak can can't hold high oil pressure, but will hold pressure enough to keep oil flowing through the galleys in the motor.

To help this along is to use10w/30 and nothing thinner. You can use thicker but that little motor doesn't like the thick stuff too well.

As long as oil it getting up to the head and swirling around in the head at idle, oil pressure is actually fine. The light comes on just as a warning that a set minimum oil pressure parameter is not being met, but this doesn't mean total loss of oil pressure.

It's a common, esp with a block with 230K miles on it to have tired main bearings.

 

[FadedBlue]

Ummm...hate to say it, but with a block with that many miles, no new oil pump will bring your pressure back to normal since the main connecting rod bearings are super tired and letting oil go past them-why you're losing oil pressure at idle. They can be tight as mischif mentions, but just worn enough to allow oil to flow past them.

If the oil gauge needle pegs at normal when the oil is cold, then falls to nothing when oil is hot, that's a definite sign that the main bearings are weak can can't hold high oil pressure, but will hold pressure enough to keep oil flowing through the galleys in the motor.

To help this along is to use10w/30 and nothing thinner. You can use thicker but that little motor doesn't like the thick stuff too well.

As long as oil it getting up to the head and swirling around in the head at idle, oil pressure is actually fine. The light comes on just as a warning that a set minimum oil pressure parameter is not being met, but this doesn't mean total loss of oil pressure.

It's a common, esp with a block with 230K miles on it to have tired main bearings.

Well when it is cold the oil pressure is right where it should be then goes down when the car is warm, wish I had known this was the bearings and not the oil pump as I already bought it and its in my house now. So basically I have bought an oil pump that I now have really no use for. Still putting it in since I have it but basically I spent 80 for nothing being 18 in college and looking for a job means money is insanely hard to come by. So what is my likely cost to replace the bearings on it? I should be getting about 160 from my buddy soon so it is possible that I could get this bearing issue out of the way then. Would it be relatively safe to drive as is once I fire it back up? I could slip the throttle body back on and be good to go hopefully?

 

[DSM1G90]

No, keep the pump since you can use it on an overhaul down the road, for the inners do get worn but not bad.

Trick on doing bearings is if the crank is in rebuildable condition to allow new bearing to be installed due to the fact that the new bearings have to 'seat' around the crank journals for a perfect seal. You might be lucky to have a good crank where a bearing replacement alone will cure the pressure condition.

But, for now, where I mentioned before: if you got oil swirling around in the head at idle (you may have to increase the idle speed close to 1000 rpm to get that oil light out, but that buys you the min pressure needed,esp with the oil being thinned down when it gets hot), you should be fine to run the motor as long as you need like that since oil is getting throughout the block and head with no problems.

Why I'm telling you all this is that my Turbo Laser is experiencing the same condition: decent pressure at cold, but gauge drops to nil when hot at idle ...

(now, my 1.8L Auto DD 1991 Eclipse with 206K miles on it is a different story-oil pressure is plentiful and that needle remains at 12:00 when the oil is hot-letting me know this little motor is still super tight, but have tired valve guides since it smokes a little on startup after sitting overnight)

... and this condition was present when I got the vehicle over 5 years ago. I know I have tired journal bearings allowing pressure to drop when the oil gets thin, but as long I see oil swirling up in the head when you look in through the oil fill hole in the head, I'll be fine. ..... and I've been cross country freeway driving and stuck on 29000 miles on the car after my purchase ... and with same low pressure at idle condtion as you are experiencing and the thing still runs like a top.

Eventually, It'll be needing that overhaul - both top and bottom - but right now, it's not a pressing issue that need desparate attention.

Thus, in a nutshell - you'll be fine until that time for overhaul is needed, which is not right now.

Good luck as always - DSM

 

[FadedBlue]

Ok thanks man that puts me at ease, I'll just change the oil put my throttle body back on set my idle at 1000 and delete the AC while I'm at it.