Fuel, spark, no compression = no start

[90 GSX]

Please take the time to read this post and help me as it will be greatly appreciated. This fiasco started when I pulled off my throttle body to replace it with a TB with fresh shaft seals. At the same time, I decided to do the vacuum line delete mods including the EGR blockoff plate. One of the EGR bolts snapped while I was removing it (threads galled and locked). I put it on with only one bolt thinking it would seal... WRONG.

It made a whistle sound under boost and idled crappy, low vacuum all that stuff BUT it was still running mind you. I didn't have time to fix it so I left the car for about 4-5 days just sittin there. I went to start it up one day to do some diagnosis and the damn thing doesn't start up. All the while, I knew that my intake manifold gasket was bad, so I decided to pull it off and replace it with mitsubishi gasket and heli-coil the EGR bolt hole. Did the repairs (and I am a very competent mechanic). Car didn't want to start, so I started the diagnosis process. The following are things I checked that were good:

-Boost/Vacuum leaks
-ECU caps
-CAS
-ISC, TPS, Throttle position switch
-Coil/PT (car has spark and I tested w/ multimeter)
-Fuel pump, MPI fuse, MFI relay, and injectors (car has fuel and good pressure)
-Timing belt is still there and seems to be tensioned properly

After checking all that stuff, I decided to pull the plugs and check them out. Pulled them out and almost got knocked out from the fuel smell from all that cranking I did trying to get the car started. Dried the cylinders, dried the plugs, still no start. Found out that the wire to the coolant temp sensor was not getting voltage, ran a new wire and voila, engine coolant temp is working. Dried the plugs/cylinder again AND I changed the oil because the dipstick smelled fuelly (if that's a word). Still not start.

Add these to the list of checked good items:
-Spark Plugs
-Coolant temp sensor

I just today purchased a compression tester. I hooked it up about an hour ago and did dry and wet compression tests.

Dry (1-2-3-4): 45-40-30-40
Wet (1-2-3-4): 62-58-45-60

I got those numbers from memory so they may be a little off, but who cares the numbers should be at least double of what they are. #3 has always been a little lower than the rest since I bought the car.

Back to the issue at hand, I have a couple ideas - jumped time, or piston rings. Could bad piston rings ALONE cause the compression to be that low on ALL cylinders? The last time I tested the compression it was between 125-135, not great but it did the job and it didn't smoke at all. The car has been running a bit lean since I have had because of misc. problems I had to fix like boost leaks, ecu issues, and garbage like that, but it never went below 0.85 or 0.87 volts on the datalogger. However, the day this happened (the snapped EGR bolt and the new throttle body), I took it for a test drive and ran it under boost a couple times and it dipped down into 0.83. That's part of the reason I stopped driving the car, so I could fix the lean condition. Could that be enough to toast a ring? I don't know how to convert voltage to wideband numbers, but I'm sure it's not THAT bad. Even then, would the cylinder closest to the EGR be most affected? The comrpession numbers don't seem to think that's the case. The car is stock, with 10 psi set by an MBC, it also has an EPROM chip with RC 550's. No other power mods. I find it hard that such light abuse could kill piston rings but I could be wrong. The car showed no signs of what was to come, and it's almost like something happened to the car while I was not driving it...

My other theory is that it jumped time. How can I check if it did? Do I have to remove the timing cover? Is there a guide or something? I have done a timing belt before so I am pretty good with that general area of the car, but do you need to remove all the pullies and all that stuff just to check if you are still in time? I am thinking it jumped time because the compression test gave me numbers that are almost exact ratios with my last compression test when the car was running (did that make sense???). Every single ring would have to have lost the same amount of compression if it were piston rings. That why I think it vavle timing...

HELP!!!!!!!!!!!!!!!! I have a 6-bolt motor that I'm building right now as we speak but it's not done yet! I need this thing to last just a little while longer. Plus I'm driving around my heads/cam/supercharger trans-am in the meantime, which sure as hell ain't no daily driver.

 

[Bastard1g]

I would suspect headgasket first. Head gaskets blow pretty easy if you dont watch out. I popped 3 within 2 months before. Then I learned to turn the boost down. That was about 5 years ago. So I would pull the head and look around. If you have any questions, feel free to ask.

 

[90 GSX]

Hmm head gasket... I never considered that because there was no water in the oil. Too bad I don't have a leakdown tester. Is there any way to see whether it's a head gasket or not?

You gotta remember also, my new compression numbers are similar to my old compression numbers, meaning that they are almost exact percentages of my old numbers. When a HG goes, does it usually affect all cylinders or just one or two?

 

[Maglin]

I'm thinking it jumped time... cause of your respective numbers.... You have to pull the timing cover and check your marks... or just bring it up on TDC and check out your timing marks on the Cams... Best to pull the cover though...

 

[diambo4life]

Remove the valve cover and check whether all your rockers are in place and at the same time, drop both timing belt covers and check whether all timing marks are aligned. That should give you somewhere to start and make sure your compression gauge is not funky as well. Since you have been doing all this cranking, your battery may be a little low which can skew your numbers as well. Make sure the throttle is wide open when cranking. Hopefully, it's nothing catastrophic.

 

[gotjuice01]

a head gasket will usually affect 1or 2 cyl. -not all 4-i'd go for the timing first.(cam timing that is)good luck!

 

[Bastard1g]

Head gaskets can do weird things. They dont usually do anything. I would deff. check your cam timing but also, do a leak down because as he was complaining about him running lean, and now the car doesnt run. That points to internals or maybe hg. maybe burnt valves. I dont know, I am just spitting experience from stuff in the shop. Seems like bent valves would give lower numbers though. i remember a friend of mine getting 0 compression in one of his cylinders after his balance shaft belt ate up his timing belt.

 

[90 GSX]

Thanks for all the responses guys... i actually didn't hold my foot on the gas while I did the test. Would it really have that much of an effect?

Also, whats the easiest way to get the bottom timing cover off?

 

[gotjuice01]

true, there is a number of things it "could" be. you really need to get a leakdown tester .if you don't have one-auto zone and other "walmart type" parts stores sometimes rent these items out .that is really were you should start.OH--just so you guys and gals know i'm not talking out the side of my neck.Yes i'm new to DSM's-but not to wrenching or racing,over 20yrs exp. @ both.I'm just trying to share some knowledge.thanks for listening.good luck with your DSM-oh,yes you need to hold TB wide open while doing comp. test.it will make a difference.don't forget to disable fuel system if you already have not done so.

 

[DsMWookie]

Well I didn't see if you replaced the plugs after seeing that they were soaked in gas and I had the same thing happen replaced the plugs and voila....just had been fouled out.


But as far as the compression tests go.....I believe the engine has to be to operating temperature efore you do a proper test otherwise the numbers will be ####ed up.

 

[CatchMe]

I'm thinking it jumped time... cause of your respective numbers.... You have to pull the timing cover and check your marks... or just bring it up on TDC and check out your timing marks on the Cams... Best to pull the cover though...

I agree. Timing sounds like it has jumped thats why the compression in all cyclinders proportionatly droped that like that. You should check your timing on the cams first - make sure the lines match up and if they do - then move on to checking the timing on the crank (along with the timing on the cams). Good luck

 

[90 GSX]

I figured that since the engine was cold the reading would not be accurate. How far off will it be on a cold engine??? I did not open the throttle either. I pulled the mfi fuse off the battery of course toc cut fuel and spark. Oh and I think somebody mentioned about the spark plugs I put brand new bpr6es ngk's in there thinking it would do something but it didn't. The old plugs had less than 5k miles on them anyway.

So what is the proper way to remove the timing cover to check the marks on the oil pump and the crank? That thing is a pain in the ass, I don't want to break it. Is there a "right" way to do it? When I bought my car it had no cover and I remember it being a pain just to install a cover I bought from somebody else! Any tips or methods would help out very much.

Once I check the timing, if it's off by one or two teeth I will reset the tension. The belt is almost brand new, the autotensioner and all the pullies are not. I just wanted them to hold until I put the new engine together. I already bought all brand new mitsubishi timing parts straight from the dealership for the new engine. However, if it did not skip, what should I look for? I hope I can just reset it but if not I need to know what I'm lookin at.

 

[Maglin]

I figured that since the engine was cold the reading would not be accurate. How far off will it be on a cold engine??? I did not open the throttle either. I pulled the mfi fuse off the battery of course toc cut fuel and spark. Oh and I think somebody mentioned about the spark plugs I put brand new bpr6es ngk's in there thinking it would do something but it didn't. The old plugs had less than 5k miles on them anyway.

So what is the proper way to remove the timing cover to check the marks on the oil pump and the crank? That thing is a pain in the ass, I don't want to break it. Is there a "right" way to do it? When I bought my car it had no cover and I remember it being a pain just to install a cover I bought from somebody else! Any tips or methods would help out very much.

Once I check the timing, if it's off by one or two teeth I will reset the tension. The belt is almost brand new, the autotensioner and all the pullies are not. I just wanted them to hold until I put the new engine together. I already bought all brand new mitsubishi timing parts straight from the dealership for the new engine. However, if it did not skip, what should I look for? I hope I can just reset it but if not I need to know what I'm lookin at.

Oh now we have some good info. You at least need to get a new tensioner. If your timing belt skipped timing it's probably not do to it stretching as belts don't stretch all that much. It's usually due to a weakend tensioner. Mine jumped time on a -60 degree F. day cause the tensioner was so stiff it didn't take up the slack fast enough on engine start. I just retimed it and have since babied it. I now have all new pulleys, Tensioner, and a New Mitsu TBelt. So if it has jumped before and now it probably did it again it's probably due to the old tensioner. I would get the pulleys along with it as they are not to expensive and will ensure you have a properly working timing drive system for some time to come.

I'm starting to wonder if all these jumped timing issues is due to lightened ineartia ie.. Lightweight Flywheel, Lightweight Crank Pulley, and Balance Shaft removal. Like the motor is reving so much faster that the old tired tensioner just can't compensate fast enough anymore and thus it starts jumping teeth and belt valves and dinged up pistons are the expensive end result. Just a thought.

 

[90 GSX]

Maglin, I think you may be right... an old tensioner probably can't react as quickly to large changes in stress on the belt. I will try retensioning the belt if it skipped. I don't want to replace the tensioner, I am building a motor in my garage right now with 2g pistons .020 over with a rebuilt lightly ported (more like cleaned up). I bought 350 bucks worth of mitsubishi timing parts, I would hate to have to buy another 80 dollar autotensioner just to use it for a few thousand miles and then put it out of comission.

If it did skip what else do I need to look for? Like how will I know if I bent any valves or such? When the timing skipped before it didn't mess any valvetrain parts up. How many teeth can the crank skip before it bends any valves? What about one of the cams???

 

[90 GSX]

UPDATE

I finally got around to pulling the timing cover off and to my dismay, all the timing marks are still aligned and both belts are tensioned and in tact. So basically that means that my compression loss is one of the following:

-Head gasket (highly unlikely, all 4 cylinders have bad numbers, car barely lost any coolant)
-Rings (Highly possible, but what would make the numbers drop so hard on every cylinder)

Is there anything else it could be? Bent valves would mean 0 compression right? Or is that only when all 16 are bent?

HELP ME!

 

[Bastard1g]

Do you have access to an air compressor? I would try to do a leak down test. I am still thinking hg instead of piston rings. I would think the valves would be burned up before the piston rings would be smoked, but I may be wrong. DO you know how to do a leak down test? I think there is a vfaq for one.

 

[DSMeclipse4G63]

with all that fuel your talking about getting into the oil means bad rings not head gasket. With you trying to start the car with all that fuel swishing in there probly worsened(not a word but oh well) the situation. With all that fuel and movement most likely scored the cylinder walls. I would say you need new rings, and if its not too bad you can hone the cylinders, otherwise youll be in for a block as well.Just my .02cents(I am too a very competent certified mechanic/tech)
Andrew

EDIT : I also forgot that your injectors are probly leaking which flooded the CC'S(combustion chambers) and the initial trying to start probly did the "deed"

 

[90 GSX]

I don't think that is what's wrong... How can you lose 60-80 psi of compression that way? You gotta remember, the car wouldn't start before AND after I tried the cranking deal. I only cranked the car a few times before I started investigating the no start issue. After that initial series of cranks, I squirted oil in the cylinder and let the fuel dry out before cranking again and when I did crank I pulled the MPI fuse by the battery. Most of the time I was fixing other problems and not even cranking the thing.

I think what bastard1g said is right, no way to know for sure without a leakdown test.

Also, my injectors are brand new RC 550's and they are not leaking. The reason so much gas was dumped (if you read my earlier post) was because my coolant temp sensor had a break in the wire.

Regardless of the issue, the motor was tired anyway. I'm going to start building the new motor, it would just help if I had something to drive instead of a 500 horsepower blown v8 around daily.

 

[peregrine]

sounds like you washed your rings.

 

[DSMeclipse4G63]

sounds like you washed your rings.

my point exactly ........

 

[peregrine]

my point exactly ........

:laugh:

 

[1fast97gsx]

at least they are nice and clean right?