car problem

[tnm27]

i have a 91 eclipse. i don't know what the problem is but there is what happened. i was on the highway and thought i'd try the car out. so i downshift from fifth to fourth and nothing but when i downshift to third at about the 5,500 rpm the car started to stumble, it sounded like maybe it was backfiring as well, and it wouldn't go pass 5,500 rpm. if any knows what the problem is or what is causing it to act like that any info would help. thanks.

[xveganxcowboyx]

Some more info on the car would help.

If it is turbo I would check your intercooler piping. Look for leaking couplers or anything else out of the ordinary. It's a good place to start.

[HiImBrian]

Sorta sounds like fuel cut.

[DBMajik]

The first thing I would check is your base timing, since it's the easiest. Then go to boost leaks. Then ECU caps.

[tnm27]

here is what i have in my car:

stock 91 turbo awd ecu
stock fuel system
stock 14b
greddy type s bov
3in apex exahust system with n1 muffler
cometic headgasket
...thats all i can name that really has anything to do with the motor or anything that has to do with this problem..


i checked all piping and seems to be good...timing i will do soon (once this snow storm is over and i can get my car to the garage)...as for ecu caps, the ecu is doing fine...i've been able to pull with this ecu w/out this problem occuring. this is a first.


one thing i should mention though. i don't know if it has anything to do with the subject but yea...i bought another ecu recently and the guy said that the caps needed to be replace soon. i put it on the car and the same thing happened but at 4000 rpm...it was staggering and backfiring...etc.. than i switched it with the normal one and now its happening to that one...(thats the one i have on now) just a thought. if it matter. :)

thanks guys.

[tnm27]

Sorta sounds like fuel cut.


can u go into depth? sorry, i'm ma noob to the dsm...so yea. i have noticed though, something fishy or funny bout the fuel gauge and my fuel...hmmm...thanks.

[DBMajik]

can u go into depth? sorry, i'm ma noob to the dsm...so yea. i have noticed though, something fishy or funny bout the fuel gauge and my fuel...hmmm...thanks.


It can't be fuel cut unless you're over 19psi. However you'll feel it when you hit fuel cut. :lol:

A galant vr-4 I was looking at buying had this same problem and I never actually figured it out. Bringing the base timing down did help, but didn't completely rid the problem. However I never did a boost leak test.

My next guess would be the fuel pump, after a good boost leak test.
To do boost leak tests you should use soapy water on the couplers.

[HiImBrian]

Yea your right its not fuel cut. I didn't know what turbo and how much psi u were running. Fuel cut is pretty much when you have more air than fuel going into your engine and your engine kinda gets drained and stops accelerating for a sec.

[tnm27]

i am running about 12 psi with a 14b.

[Pushit2.0]

Fuel cut is pretty much when you have more air than fuel going into your engine and your engine kinda gets drained and stops accelerating for a sec.
No, fuel cut is the ECU shutting off the fuel injectors, this happens when the mas airflow sensor reads to many Hz(to much air). Check for: Boost leaks, fuel pressure/flow problems, base timing, plug wires, coil packs, transistor pack, injectors failing, fouled plugs, that is where I would start looking.

~John