Heavy Rich; Can't rev past 2500

[67goatpimp]

I bought this car today i don't really know much about it, but from what i can tell it's a 4g63t swapped 90 gs ecclipse.

the car runs and idles but it HEAVY rich and will turn the ground black underneath the exhaust. I got two ECUs with the car and 8625 which i have in the car now and it will drive up to 2500 rpm but it's still dumping fuel. then i also have an 8624 that we tried putting in and i couldn't even drive the car. Any help on which ECU is N/A and which one is Turbo would be a good start. I drive it and it revs extremely sluggishly and is definately dumping a LOT of fuel. When i hit about 2500 rpm it starts bucking slightly and won't accelerate any farther. The turbo impeller does not spin freely but i can hear it spin when i am revving the motor. I can turn it relatively easily with a socket...but still far too much resistance.

The owner before me told me that they had tried a few MAF sensors with no luck. there is one wire run from the MAF harness to the ecu that wasn't in the original wire loom, but i'm assuming it has something to do with the swap.

 

[SuperSleeper]

I wouldn't necessarily narrow it down to electronic problems. Potentially a fuel pressure regulator malfunction.

 

[mitch83]

is the MAF plugged in.
mitch

 

[67goatpimp]

it's plugged in but it looks like they cut the connector off the MAF (possibly replaced it for the engine swap) all the wires are crimped to the wires in the original loom and there is one loose wire from the MAF run seperately from the loom to the ECU...also possibly do to the engine swap?

we don't think that it's the fuel pressure regulator because if it were, i would think it would run rich all the way up to redline or close to it...not stopping at 2500rpm

when i hit close to 2500rpm it feels kinda like fuel cut but not as dramatic...not nearly as dramatic and i can hear the engine kinda start to burble like it's possibly missing and it won't accelerate any further.

also...help with if i'm using the right ecu would be useful...it only runs with the one i have in so i would think that's the right one

 

[67goatpimp]

i researched and found the 8625 IS the turbo ECU so i have that part down...still dumping fuel though

 

[mitch83]

I still say it has somthing to do with your MAF. Possibly the wiring or somthing. Or your BISS screw is to far in. check that. where does it idle at. IF the BISS is screwed to far in when you reach about 2500 RPM or maybe even lower it will cut out and buck because it regulates the amount of air let in through the Throttle body so that would mean you would run rich and it would buck. Same goes for the maf but I dont think you would run rich cause if it's unplugged or wired up bad the ecu cant see an air flow signal unless it goes into safe mode and runs pig rich like when the O2 goes out. Check to BISS and let us know. Screw it in all the way then back it out 2-4 times and see what it does then just experment with that. then let us know.
mitch

 

[67goatpimp]

it idles right around 500rpm but the BISSwouldn't keep it from revving above 2500 in neutral (2000 in gear) anyway(thought we did dick with it). also...if you look the MAF connector....the wire just above the filled in hole is run seperately from the loom. it runs to the ECU and there's only one spot on the ecu that we believe it could fit in...put it in...seemed to drive a little smoother, accelerate faster, still stopped at 2000 but that stopped after a while...could've just been our imagination regardless it was still rich as hell.

I have a friend that has a running 4g63t that we started pullin parts off of to see if any of his good parts would make mine run... it is definately NOT the MAF or FPR. we dicked around with BISS which didn't do anything. the turbo does not spin freely though it does turn. the intercool pipe that goes from the turbo to the intercooler was disconnected when i got the car, we replaced that with no change. we tried bypassing the turbo and intercooler and it was still running really rich. another notable thing is that i can rev it to about 3500 before the engine warms up (in neutral), but only 2500 warm.

we've been brain storming as to why it won't rev above 2500. and dumping mad amounts of fuel, and possibilties that we have come up with so far are...

crank position censer
cam angle sensor
cams need to be adjusted
possibly a blown piston ring(s)?

but we think it idles way to smooth and drives too reliably for it to be anything bottom end. we are going to compression check the engine tomorrow and see what else we can do *shrugs*


any help would be appreciated this is really frustrating.

 

[mitch83]

I dont see any of those being a factor in the car running rich or not reving over 2500rpm. The cam angle sensor really only deals with timing and you dont have a seperate crank angle sensor unless they swapped in a 7 bolt motor. The 6 bolts cam and crank angle sensor is the same thing. If the cam angle sensor is out of adjustment then it would just set your timing way back and you would be hella slow. You can easily check it by looking at it if its set back toward the cabin then it's retarded but if it angles toward the front its advanced it should sit around the middle that would put you close to where you need to be. And as far as a blown ring goes I dont see that causing any RPM problems all thoes would just hurt your performance. RPM problems and running super rich is going to be a sensor or fuel problem. It isnt going to be a machinical issue.
mitch

 

[67goatpimp]

mitch: any idea on the jerry rigged MAF wire?

 

[mitch83]

This may be somthing to look at as far as your rich situation goes is thier vacum line coming from the FPR if so does it go to a solenoid on the driver side of the car. Do you have a datalogger I doubt it but I wonder if you TPS sensor might be out of adjustment. That would cause those types of problems not 100% exactly but similar ones. If you dont have a datalogger to check the position then go to VFaq thier is a write on using an OHM meter to adjust your TPS. You have 3 pins on the TPS connector you have to OHM them. I'm also wondering about the condition of your turbo that wouldnt cause any of those problems.

If your MAF was bad or the wiring was jacked it would cause what your talking about I know this because I ran my car with the MAF unplugged and it did that exact thing. The car will run hella rich and will not go over a certain RPM for me it was 2500rpm because the ecu is protecting the engine. Get a wireing diagram and see if the wires match what you have. Work out those problems and see what happens. I'll see if I can find a MAF wiring digram.
mitch

 

[67goatpimp]

the turbo is definately spinning...and i doubt it has ANYTHING to do with this problem cuz we tried bypassing the turbo and intercooler altogether...intake-throttle body...and it made no change...we did see the turbo was spinning though...our guess is that it will work just take longer to spool than it should...i'll get a new one when i can but money is uber tight right now

 

[mitch83]

your right the turbo would just suck ass and would not produce good boost. Is it the stock T25. I would swing by dsmtrader and pick up a used 14B for like $50-100 you'll have to get an install kit but a 14B is a really good low budget turbo thier are like 4-5 guys running 11-12's on it almost all stock with hella good tuning so. Thats if your money is hella tight. but if you can swing $500 then pick up a 16g. But get this problem fixed first. Did you boost leak test the system for boost leaks. make sure all the vacum lines are attaced.

You should have a vacum line going from the passenger side of the valve cover going to the intake, one going from the back of the valve cover to the intake manifold,one from the FPR to a solenoid on the driver side, if you have a 1G 6bolt then you should have 3 from the TB, ofcourse you'll have the lines from the turbo and wastegate to the boost solenoid, and thier are like 3 others that I cant think of right now but check those that I mentioned and make sure thier thier. It's hard to diagnose a problem like this when the car has gone from non turbo to turbo cause you dont know what was left out.
mitch

 

[67goatpimp]

it's either a 14b or a small 16g...goin...goin...gone either way though...*shrugs*

and my biggest guess is that it's the wiring for the MAF....not sure why that one wire is run seperate from the rest of the harness...i don't see why it would be neccessary for the turbo but not for N/A....and even then...the other end isn't hooked up to the ECU. i found a hole in one of the harnesses for the ecu that it looks like it should/could go in...but either way it doesn't stay in.

 

[67goatpimp]

did a compression test to see how everything is hitting, here's the results:

180 180 175 180

i also found out that the wire on the MAF that is run funky is not neccessary on non-awd models...not sure if that's true...but what i heard...can anyone confirm this?

 

[AWDPSI]

just a thought.....is the maf that is in there a 1g or 2g. You talked about it being wired with connectors maybe they wired up a 2g mas. that is a popular mod amoung 1g peeps. Next make sure those wires are hooked up correct and are good connections. Just things to try.....also make sure your fuel filter isnt clogged....I know its dumb but you never know

scott

 

[turboholic]

http://www.vfaq.com/mods/ECUs.html
http://www.vfaq.com/mods/2GMAF-1G.html
http://www.vfaq.com/mods/ecu-harness-1G.html

-Did you do a test on the intake system(IC pipes) to make sure there's no leak? Can you increase the RPM slowly without building boost (boost gause stay below 0) if yes will it pass 2500?

 

[92awddsm]

The turbo mas is differant than the nonturbo. All turbo cars have that extra wire going to the mas.
Check the coolant temp sensor. It might no be plugged in or working at all and will cause similar problems.
What size are the injectors? If you dont know, tell us what color they are.

 

[67goatpimp]

the boost gauge doesn't work so i dunno...and i'm pretty sure it's not makin boost at all or not much...we vented the BOV to atmostphere so we could hear it cuz i don't have the money for another gauge and we wanted to know if i was making ANY boost, but we can't hear it. and they injectors are either green or grey maybe *shrugs*

also...so they all have that extra wire...what the hell do i do with it? i would be glad to wire it up correctly if i knew what correctly was.

and why would the fuel filter being clogged cause it to run pig rich?

 

[92awddsm]

1-The injectors should be the blue tops. It should also have a resistor box wired into the injector circuit.

2-On a turbo wiring harness, the "extra"wire is already included. On a non turbo with a swap, it has to be run sepeately unless you want to split the harness open all the way back to the ecu just to run the extra wire. Just find a good, out of the way location and secure it so it doesnt get pulled or broken.

3-Did you check the coolant temp sensor? It is located on the thermostat housing.

 

[67goatpimp]

i haven't checked that collant temp sensor yet, but i know the gauge works.

also...i'm looking at those ECU diagrams for that extra wire...i can't figure out where exactly it needs to be put in...there's one area on one plug for the ecu that looks like it has been modded, but that doesn't look like it's where this wire goes. *shrugs*

checked the plugs....blue top