Strange, intermittent engine issue..

[XtremeRS2gnt]

I did a fresh stock 6 bolt rebuild on my 92 Laser AWD, and it runs excellent. There is only one issues, which is very intermittent, only happens like once a week maybe. I'll be accelerating from a stop, and when i'm still in 1st gear, the engine cuts out sort of, like it's hitting fuel cut, or a rev limiter maybe. The engine just studders, give it gas and it goes nowhere. It's hard to tell if its fuel related, or ignition..I dont know, its very strange and inconsistant. The car is mostly stock, with a 16g, walboro 255, and and aeromotove FPR set to 37 psi static(0 psi). Any ideas? Anyone else have an issue like this? The plugs are brand new, used Taylor wires, but they look "ok". The wires were next on my diagnosis anyway. I don't know if a failing PTU could cause this issue or not? . thanks for any info.

 

[DanThMan1983]

I did a fresh stock 6 bolt rebuild on my 92 Laser AWD, and it runs excellent. There is only one issues, which is very intermittent, only happens like once a week maybe. I'll be accelerating from a stop, and when i'm still in 1st gear, the engine cuts out sort of, like it's hitting fuel cut, or a rev limiter maybe. The engine just studders, give it gas and it goes nowhere. It's hard to tell if its fuel related, or ignition..I dont know, its very strange and inconsistant. The car is mostly stock, with a 16g, walboro 255, and and aeromotove FPR set to 37 psi static(0 psi). Any ideas? Anyone else have an issue like this? The plugs are brand new, used Taylor wires, but they look "ok". The wires were next on my diagnosis anyway. I don't know if a failing PTU could cause this issue or not? . thanks for any info.

well thats very strange. the clutch isnt slipping or something is it?

 

[LordDigi]

... aeromotove FPR set to 37 psi static(0 psi) ...

I'm assuming that you got the FPR that is for a turbo aplication that will increase FP base upon boost ... I'm pretty sure you got the right one, but ya never know

I think the easiest thing for you to do right now is a buy/borrow a logger and try to log this event ... I beleive that would shine some light on things. Check for boost leaks ... Could be a faulty MAS ...

 

[XtremeRS2gnt]

I'm assuming that you got the FPR that is for a turbo aplication that will increase FP base upon boost ... I'm pretty sure you got the right one, but ya never know

I think the easiest thing for you to do right now is a buy/borrow a logger and try to log this event ... I beleive that would shine some light on things. Check for boost leaks ... Could be a faulty MAS ...

Yep, I have the Aeromotive 13105, just like the 13109 most everyone else gets, but just one IN port, instead of 2. It's a boost referencing regulator. Actually, I just ordered a logger last week, and it will be here in a day or two, so i'll have to go from there. It makes me wonder if it's a electrical connection issue somewhere, since it's only intermittent and such..It's going to be difficult to have the logger out and running when it happens though..

 

[FORMONTOYA]

I'll ask the dumb question.....fuel filter was last changed when?

Is it just 1st gear only?

What RPM?

After you dropped the engine in, you leak tested it, right?

What do you do to get it back under control (let off the gas......shift to 2nd...etc)?

 

[wishihadatalon]

Its a DSM Matt. That is the biggest problem I am stumped on this one too. Just like I am stumped on my super wierd misfire at part throttle.

 

[XtremeRS2gnt]

I'll ask the dumb question.....fuel filter was last changed when?

Is it just 1st gear only?

What RPM?

After you dropped the engine in, you leak tested it, right?

What do you do to get it back under control (let off the gas......shift to 2nd...etc)?

Fuel filter was not changed..although I'm confident its not a mechanical fuel delivery issue..if it were a clogged filter, the engine would be running poorly most of the time, and under boost. It runs great all the time, and i've had it up to 14 psi boost, and it runs rich at that.

From what i've noticed, its only happened in 1st gear, from a stop, accelerating, prob in the 2000-2500 rpm range.

We did a boost leak test, and the only place of a very tiny leak was the throttle plate shaft seal...fairly common.

All i do is let off the gas, and get back on it, and it goes away after a few seconds..then all is fine for a long time..just strange

 

[wishihadatalon]

Hey Matt, Brandy's car used to do this. It stopped but I was fairly confident that the lifters were to loud and the motor was just seeing it as knock and pulling the timing very far back.

 

[XtremeRS2gnt]

Hey Matt, Brandy's car used to do this. It stopped but I was fairly confident that the lifters were to loud and the motor was just seeing it as knock and pulling the timing very far back.

Hmm really..Well the lifter tick the engine had when first started after the rebuild, is now completely gone..I havent heard them tick since then, and now the motor has like 500 miles on it. The logger cable is coming in today, so we will see if i can get lucky and have it on when it happens.. Almost seems like it's loosing the MAS signal or something for a few seconds?

 

[XtremeRS2gnt]

Ok, now we are getting somewhere..Got the logger up and running, and it's showing a code 44, Ignition coil.. It's strange, i never saw the Check Engine light ever come on before..didnt even think to check for codes! This morning it happened pretty bad, almost for like 5 seconds, i can tell its dropping half the coil pack, 2 cylinders.This time, it turned on the Check Engine light, then went out...I'm going to check the connectors and pins on the PTU and coilpack, hopefully it's something easy like a corroded pin, or bad connection..I would think if its a failing coilpack or PTU, it would just fail, not be intermittent??

 

[wishihadatalon]

Ok, now we are getting somewhere..Got the logger up and running, and it's showing a code 44, Ignition coil.. It's strange, i never saw the Check Engine light ever come on before..didnt even think to check for codes! This morning it happened pretty bad, almost for like 5 seconds, i can tell its dropping half the coil pack, 2 cylinders.This time, it turned on the Check Engine light, then went out...I'm going to check the connectors and pins on the PTU and coilpack, hopefully it's something easy like a corroded pin, or bad connection..I would think if its a failing coilpack or PTU, it would just fail, not be intermittent??

sometimes they go out slow. Remember its a dsm

 

[XtremeRS2gnt]

Well all the wiring, pins, and connectors look fine, were tight, and no corrosion. I put small amounts of dielectric greese on each pin for the coilpack and PTU, and so far its ok, but if it happens again, i'd be looking at more of a hardware issue with the coil or PTU..

Yeah, i know its a DSM, but if man built it, man can fix it

 

[LordDigi]

... Could be a faulty MAS ...

Check your connections around your MAS it could be some condensation forming inside shorting it out ... keep an eye on the logger it will point you in the right direction

 

[XtremeRS2gnt]

Well i'm still having the issue..its giving a code 44 for igntion coil..I can tell it's dropping 2 cylinders out when it happens. I opened up the ECU and replaced the caps in there..the old ones didnt really seem to be leaking, if anything, a very, very small amount if any. It hasn't done anything since then, but that was only yesterday, and it can go days even up to a week without mishap..I'm really thinking the PTU is on its way out..

 

[timloomis]

Mine is doing the same thing,but at idle,cruising,and sometimes wot,.Ive changed coil packs,transistors,plugs,wires,etc...Im also thinking my ecu is bad now,its showing crazy readings on the logger when it misses.Ive even changed the caps,but you never know.