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Fuel system problem

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UCSLugRacerX

15+ Year Contributor
166
0
Jun 9, 2004
Santa Cruz, California
My 1G has been dead for over week now, and I'm still scratching my head as to what the fix is. Here is the situation:
- It’s spark on all 4 plugs
- I replaced the 3 caps on the ECU. (Plus, it’s a next to new ECU)
- The Fuel control relay was tested and checks out fine
- The fuel pump is fine, and I can hear it when I crank the starter
- the CAS has not been touched
- brand new fuel filter (so I made sure it wasn’t clogged.)
- new/ replaced idle speed screw. (and set it to approx. 750 RPM’s at idle)

-The timing belt was recently done, but I checked the timing marks and ALL of them line up perfectly. (crankshaft pulley, oil pump pulley, cam sprockets, front balance shaft, and the hidden rear balance shaft.)
-Although I did notice that I have a strange cut in the timing belt itself, (Which means I’ll be doing the timing belt job again.)
-Idle pulley, and tensioner pulley, automatic tensioner, and tensioner arm assembly was replaced.
-When I attempt to start it, it runs over but doesn’t fire.

Also, the engine stopped working while I was driving on the freeway, and I noticed that the engine was making somewhat of a hissing sound, plus my Air/fuel ratio gauge was indicated it was running rich. (It was on the first green bar on rich side.)

-I had a check engine light when it died, but I didn’t have enough time to get a code reader on it. And when I put the key in the On position, the C.E.L. does not light up anymore. (Considering the ECU is Programmed Read Only Memory “P.R.O.M,” it won’t tell me what was going on.)

---So, if I am getting spark, then it must be a fuel problem. Is there another component in the fuel system schematics that I overlooked? Why would the engine die all of a sudden after operating fine for 13 miles? Fuel problem? Ignition? Timing? Faulty, or broken or leaky injectors?—Although my A/F gauge said I was running RICH, just MOMENTS before it died. Could the engine be flooded with fuel?

Please help me with this process of elimination. Any help is appreciated.
And if you live in the Bay Area, in Northern CA, I will pay you if you come by and can figure out and fix the problem.


Thanks!
-Andrew
 
No boost leak. Plus a boost leak won't stop the car from starting.

The compression was fine all across the board.
 
I feel your pain man, I am clueless I have the same exact problem with my 2g its been dead for 3 weeks now.
 
So here's what's happened so far. I pulled the fuel rail out and held the injectors up to a piece of paper, and cranked the motor over. The injectors were spraying on all 4! Also, there's plenty of fuel getting to the fuel rail, as I made a mess in my engine bay, upon checking the fuel lines.
I am getting spark on all 4 plugs still, and I checked my camshaft angle sensor (rotating it with it disconnected to the intake camshaft) and it makes noises when I turn it by hand.
Although, I heard more of a wooshing sound, or gurgling sound, rather than the distinct fuel injector "CLICK."

Also, Steve (a DSMtuner member) also gave me test instructions for my MPI relay, and the MPI relay checked out fine.

I Also bought a CAS, and a new fuel relay to see if either was the problem, but niether worked.
Also, the car was not overeating when it died while driving on the freeway. Engine temp was right in the middle and there was no smoke coming from either under the hood, or under the car. And when I stopped to look under the hood immediatly after the car died, there was no white smoke, or steam, or oil leaks, or anything of that nature.
----------------

So, here's what the problem is NOT:
Fuel pump
MPI relay (aka Fuel control relay)
fuel injectors
fuel filter
fuel rail
spark plugs,
plug wires
ECU (and ECU caps)
coil pack
cylinder compression
timing belt setting
camshaft angle sensor
ingition fuses,
ANY fuse in the car (All fuses OK)
----------------------------------

Here is what I have not checked, but I heavily doubt it's the culprit:
power transistor
electric starter
starter solinoid

I've also checked EVERY single engine wiring harness connection, and there are none that are loose, nor are there any loose hoses, or vacuume hoses.
----------

I REALLY NEED HELP GUYS! I HAVE NO IDEA WHAT ELSE IT IS. I am seriously thinking of towing the GSX to Pick-N-Pull, and getting like $300 bucks the piece of shit.
Any help is greatly appreciated.
 
While cranking over the engine, while I was checking if there was spark at all 4 wires, there was a spark, but it was a FAINT orangeish-yellow spark. According to the Haynes manual, there should be a distint BLUE spark. Perhaps there's not enough ecletricity to spark the air/fuel mixture? My plugs are fine, and not fouled.

Also, my plugs are wet, when I removed them, so I must be getting fuel.


Any thoughts are appreciated.
 
sounds like its the ignighter.
if the plugs are wet then you are not getting spark or enough spark to set the fuel.
Change wires, plugs and if that does not solve the issue go for the coil and or ignighter.

Check your pm
 
Well it certainly sounds like your getting enough fuel. I would say your problem is electrical. Weak spark with the plugs out is only weaker (or non-existant) when they're in and under compression. Spark should be strong (and blue) when out. Did you replace the plugs? Weak spark is usually a weak coil - have it tested. Then check all ignition wiring connections for clean and tight and no internal breaks in the wires - also battery connections (remove and clean them). Make sure battery has a measured 12v when cranking - also 12v on one side of the coil while cranking. Then test or swap the power transistor unit. Last suspect the ECU.
 
Thanks for the help guys. My plugs are new, as are my plug wires. I made sure that all teh connections to the plugs, and the coil pack are all tight and connected. Although I'm suspecting the coil-pack. This would explain the my A/F ratio gauge reading very rich, because the fuel was not being burned.
I have checked my ECU, again, and again, and then checked it again with a magnifying glass, and bright flood lights. Everything looks fine. Nothing looks burned, and nothing smells bad.
When I do try and crank over the starter, the starter works at proper speed, and very much seems to be getting proper voltage. When I try to crank over the engine, I hook it up to my running Honda Civic's battery, and borrow it's alternator power, which is well over 12 volts. (It's like 13 or 14 volts)

What other components in the ignition system, affect the power of the spark other than the coil pack, and power transistor? Also, where is the power transistor located?
I definitly am getting enough fuel, because when I pull my plugs out they are damp, and wet with fuel. (And I smell fuel on them too.)
 
The transister is at the base of the coil harness plug.
See if a friend of yours will let you borrow there coil and trans and see if it solves the issue.
Should only take 10 min to swap them out if both cars are cool.( dont like to burn self on engine hehe)
 
Here are pictures of my coil pack. Before I cleaned it off, there was alot of oil and fuel and dirt all over the wires, connectors, etc... I took apart the coil-pack, and cleaned it as much as I could with the rags, re-tightended the connections and re-installed it back on the car.
I think that this coil pack is broken, because it only will give me a WEAK spark, and not a distinct strong BLUE spark.
Can I pull a coil pack from any 1G 4G63 engine? I know that the fireing order on the cars are different, so I know it wouldn't work if I installed it right off. The car is a 90 GSX, and I was wondering if the "TACHO interface J602" controls the sequence of the coil firing, and if I just replaced the coil, but used the same "tacho interface" (assuming the interface is still good).
Here are pics of the part number, and the part which I'm talking about.
 

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Have you checked that one stupid wire all the way to the right of the thermostat housing? Its a typr of sensor. My car wouldnt start b/c it was disconnected. Make sure all those wires on the thermostat housing are connected. I had somewhat of the same issue you had about a year ago and I checked everything you did. Give it a try, it does hurt.
 
I really think it's your coil (1st) or power transistor (2nd) but another small possibility (if it's neither of those) is a bad filter capacitor (near coil - often on intake manifold - looks like a small cylindrical aluminum can with 1 wire out of it) which if bad can affect spark generation (and it's cheap).
 
I've checked every single mother F*king plug and wire in the engine bay, and unplugged, and re-plugged, and cleaned all connections and wires as best I could.
I have not yet, though, done the Ohm meter test on either the coil pack (when installed) and the power transistor. I hope it's one of those.
Can I use any good 1G coil pack, with the TACHO interface from my 90 GSX? What does the tacho interface do?

This is a stupid question, but what does the temperature sensor look like, and where is it exactly, and what
 
I've checked every single mother F*king plug and wire in the engine bay, and unplugged, and re-plugged, and cleaned all connections and wires as best I could.
I have not yet, though, done the Ohm meter test on either the coil pack (when installed) and the power transistor. I hope it's one of those.
Can I use any good 1G coil pack, with the TACHO interface from my 90 GSX? What does the tacho interface do?

This is a stupid question, but what does the temperature sensor look like, and where is it exactly, and what is it attatched to?


thanks guys!
 
The interface is there to make the tachometer work on the 90's. The coil packs should interchange. Just unscrew your coil and screw the other back onto your stock bracket using all of your wiring.
 
If the power transistor was faulty, then there would be absolutly NO spark being sent to the spark plugs. Right? Since there is spark on the spark plugs, but the spark power is weak (and the plugs are wet when I pull them out), then this means that the coil pack has very little power. Right?

If the power transistor was bad, then there would be absolutly NO spark. Right?
 
Generally speaking (>95%) the power transistor unit either works fine or not at all. But occasionally (<3%) it may go intermittent or develop slow rise/fall times upon switching. 99% of the time a weak spark is due to a weak coil (or battery) which happens with age. And just checking that the coils resistance is proper does not guarantee that it may not be weak (if the resistance is improper, however, it is bad). Only swapping coils with a good one or doing a REAL coil test with a coil tester can properly test a coil.
 
I tested the power transistor, according to the Haynes Manual, and it checked out fine. I also bought a coil pack (the correct year and model), and that did not solve the problem either. I bought new plugs, just to make sure my plugs wern' fouled-up.

HELP!
I really am at a loss here guys. I've got no other idea why it isn't starting.

Here's again, what it's not: (i've tested everything listed below)
ECU
MPI relay
fuel pump
fuel rail
injectors
cam shaft angle sensor
coil pack
power transistor
spark plugs
plug wires
starter
battery power/terminals
noise filter
-----------------------------

When I pulled out the new plugs, the pugs were wet. This means that something in the ignition system is bad. Bu if it's not the plugs, plug wires, coil pack, ecu, or transistor, THEN WHAT ELSE COULD IT BE!!!!!

Please help. Is there another component of the ignition system which I've overlooked?
 
My new plugs have been gapped correctly, and I'm not sure if the engine might be flooded. Before I installed the new plugs, I kept the plugs out for a while, and hopefully that let the fuel evaporate from the combustion chambers. Although, this didn't help.
I'm really at a loss guys. The compression is fine across the board, and the timing marks line up.
 
I know this sucks but I havent heard anyone say anything about the FPR or its components. Im sure that isnt your problem but I would check those too. I think your solution is gonna be the one part you havent replaced yet but keep talking about. Replace the power transistor. See how that works out. You are soo close dont give up now.

Its like that bad girlfriend you just cant get rid of. :p
mike :dsm:
 
Ok guys. I thought that my ECU was the problem, due to the DSM ECU's being notorious for blowing up. I thought the ECU cap replacment work which was recently done was suspect, so I had my ECU rebuilt again, using these caps. (Also, the ECU electolytic capacitors didn't seem like they had leaked anywhere on the mother board.)
I installed the ECU after it was rebuilt, but STILL THE ENGINE DID NOT START!
I am getting spark and fuel.


I am going to check the Fuel pressure regulator, (and check the fuel pressure.) Although, what is the proper PSI for a 1G 1990 GSX 5spd?

This is really the last ####ing straw guys. I'm at the verge of taking a baseball bat to my car. :mad:
 
UCSLugRacerX said:
Ok guys. I thought that my ECU was the problem, due to the DSM ECU's being notorious for blowing up. I thought the ECU cap replacment work which was recently done was suspect, so I had my ECU rebuilt again, using these caps. (Also, the ECU electolytic capacitors didn't seem like they had leaked anywhere on the mother board.)
I installed the ECU after it was rebuilt, but STILL THE ENGINE DID NOT START!
I am getting spark and fuel.


I am going to check the Fuel pressure regulator, (and check the fuel pressure.) Although, what is the proper PSI for a 1G 1990 GSX 5spd?

This is really the last ####ing straw guys. I'm at the verge of taking a baseball bat to my car. :mad:



proper pressure i believe is 43 psi right guys?

it sounds like you have a power drain somewhere. Attach a voltage gauge to your battery and have someone crank the engine. Take a look at how far the voltage drop is. It shouldn't drop below 9 volts, if it is, you're drawing too much current and grounding somwhere.

Don't bat that gsx yet, and if you are, i got dibs.
 
UCSLugRacerX said:
My new plugs have been gapped correctly, and I'm not sure if the engine might be flooded. Before I installed the new plugs, I kept the plugs out for a while, and hopefully that let the fuel evaporate from the combustion chambers. Although, this didn't help.
I'm really at a loss guys. The compression is fine across the board, and the timing marks line up.



if you want to drain the chamber, pull the Fuel Pump fuse and crank the engine over. Its labeled MPI Relay in the haynes manual.
 
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