Small issue with the 93 Impreza

RedForester08

RedForester08

New member
93 Impreza 5mt and EJ1.8 motor with 52k miles. When I bought the car it has had this small but annoying issue. I've put 2k miles on it and have been having a slight bucking or hesitation in the mid throttle range. worse when cold. Idles perfect at 750 rpms and when cold it starts great and idles at 1500 and works it's way down the same as my other Subaru's have done. When slight to mild acceleration is when it seems to do this. I tried injector cleaner, Plug, wires and fuel/air filter. Did not change anything. It gets 30 mpg and will pull nicely to 5.5k on the tach. So 3/4 to full throttle pulls from 3k the problem does not seem to exist. If someone has any good ideas let me hear them. Coil pack , TPS, IAC, or MAF? The old plugs looked great.

Thanks

Jim

 
I'd try cleaning the MAF, and even testing the car with a good working one. When my MAF was going out it would accelerate pretty well, but I'd get hesitation and bucking when just cruising along like a normal civilian.

 
My RS did something like this when I first got it. Front o2 sensor????????????????????????? Of course you should have a CEL???????? Scan for codes????????

Does the CEL come on when you turn the key ON? I ask because someone had actually removed the bulb from my car.

 
clean the MAF first, that sounds like most likely culprit here

if that ain't it, test the O2 sensor (s) to make sure they are up to snuff. Haynes manual has specs, just pull the connectors and probe connex w/volt-ohm meter.

you HAVE looked for vac leaks and cracked vac lines already, haven't you!

 
Thanks guys I'll bring my meter home from work and check those O2 sensors and the MAF and do a better job at the vaccum lines also.

 
Check the signal from the TPS. Should be 0-5volts increasing as you open the throttle. If it spikes to zero or close to it at any spot during the throttle increase you'll need a TPS. Its a quicky and can be done with the engine off, key on.

 
Chris,

I see on the car there are 3 wires. B,W,R should I go across black to which color to test? Can I do it unplugged and measure it with ohms? Thanks for the help. I swapped a MAF with someone but no change. Did not reset ECU. No CEL Checked all the vaccum lines. all looked perfect. I lossened and retightened all the grounds on the motor and chassis. Throttle cables was pretty loose. fixed that to spec on the free play. I now have reset the ECU. we will see on the drive to work. Will do the TPS in the morninng.

 
Last edited by a moderator:
TPS works perfect. starts a .64volts goes to 4.32 at full throttle with out the meter jumping around. It does run a bit better but still a slight issues. How to check the coil packs? What dose one use to clean the MAF. the one I swapped in was from a 97 outback with the 2.5 liter twin cam. anyone think this could dtill be the issue?

Thanks

Jim

 
Clean it with carb cleaner or brake clean, and I doubt it's the coil pack, those very rarely go bad on the older N/A Subarus, but I guess there is always a chance!!

 
The MAF's from '90 all the way until 2000something when they stopped using that connector are swappable. So if the OB one was working on the OB, it should work just fine on the impreza.

 
OK guys. I have checked the MAF (swapped an actual same part one in) No change. TPS works perfect. "I" can't find any vaccum leaks. Coil packs test out perfect in specs. have done plugs wire and fuel filter. no change. Added the extra grounds. nothing. still slight stumble/hesitation between 2k and 3k around the quarter throttle. if ya nail it it will not do it or really ease your speed up with very little peddle. Is there a way to just plug the car in at Evergreen and run a diagnostic on the other sensors like coolant temp, A/F, crank sensor or knock sensor. It still gets about 30 mpg. lazy injector maybe? NO CEL. wish I had one I might have a better idea where to go next .

 
You must log in or register to reply here.
Back
Top