Hi all, i have an 86 z28 305 tpi. lately its developed a rough idle and feels hesitant at low RPM - when accelerating from a stand still.

ive got codes 32 & 44. i have replaced the o2 sensor and wires recently. the plugs tend to foul about every 3 months (i only drive it on weekends). can the egr have anything to do with the poor idle/acceleration? i was under the impression it was only involved with higher speed driving.

i have a tunerpro file from 2 days ago if that helps (in word format)

 

If I remember correctly 32 is and EGR fault, I would deffinately ck your EGR, the cars I work on now (Benz) will carbon up bad and the tubes need cleaned out usually. I think (someone correct me otherwise) the EGR operation does affect idle on you car.

 

so is it likely the egr is causing the code 44 and also the plugs to foul so quickly?

 

i have searched the forums and everyone had egr codes at higher speeds. my ses light comes on at idle and goes off after the revs go up for a while. can anyone help?

 

Clear your error codes (disconnect ECM power for about ten minutes) and see if it returns. If you get a '32' without driving the car at moderate part-throttle cruise speeds, there is a chance that either the EGR solenoid or EGR diagnostic temperature sensor has failed. The ECM will scan these inputs on startup to determine their state, and if either the solenoid or switch are grounded, you may get the code.

 

the car is with a mechanic and he has fixed the code 32. the 44 is now the problem - once the car warms up, the idle can become pretty rough and sometimes the car hesitates from take off. a couple of vaccum leaks have been fixed, MAF and fuel pressure have been tested and injectors cleaned but still getting code 44. will be checking the ecm gorunding tomorrow but is there anything else im missing???

 

Yes, apparently. FUEL!

If you have the patience, search for "code 44" and pull up a cozy chair. There are lots of possibilities. You'll probably hang up the site with all the hits.

 

The ECM uses inputs from the TPS, distributor pickup, and oxygen sensor, as well as checking the injector pulse width timing to diagnose a lean exhaust condition. The code can only set while in Closed Loop Mode.

If you still have the factory A.I.R. system installed, suggest to your mechanic that the AIR diverter valve may be leaking, and that the check valves can be temporarily capped to help determine if this is a cause of the lean condition. Of course, all of the A.I.R. hose, tubing, and fittings would need to be checked for leakage as part of this test. Any external air leakage into the left side exhaust manifold (or whichever side has the O² sensor on your car - I'm not sure on RH drive exports) will contribute to a false lean condition at the O² sensor.

 

thankyou vader. since ive had the car the AIR has never worked but i will go pay my mechanic a visit and give your suggetsions

 

when i talked to the mechanic today, he said the ecm grounding and wiring is fine. he then tried a different memcal and claims it worked fine with no rough idle and no codes.... yet - he hasnt had the chance to take it for a proper test drive. the old memcal had the numbers/letters ANY8980 on it. i thought it may have been changed before i bought the car but read another post here on TGO that this is the correct stock memcal for an 86 LB9. so my question is, can a memcal just go bad and need replacing?

 

If the egr is stuck open it will cause that very problem. major vacuum leak

 

had a code 32 but that is fixed now - egr was removed, cleaned and vacuum tested and switch was checked. when put back together, no more code 32.

im waiting to here back from the mechanic today on wether the new memcal has fixed the problem.

 

well i have no idea what is happening with this car. sometimes when you start it the ses light comes on straight away before its had a chance to warm up and stays on until the car is turned off. other times it doesnt come on at all after starting and driving it. is this the signs of an ECM going bad??

 

i think i have found my problem - the memcal is the old type and needs to be updated - read it on a tech service bulletin. the TCC used to really give me the ****s locking up ealry (installed a switch in the end) so i am guessing i have the old memcal still.

the ses coming on straight away is being caused by code 54 - i will be replacing the relay and if that doesnt work i'll do the pump

 

finally received my new memcal and it appears to have fixed my problems. idle is smooth as is acceleration - like driving a new car again! so if you have a 1986 305 TPI and your having problems, it might be worth checking your memcal for the date it was made. see here: 3rd° Tech Tips~TSB~Bugged PROM