Rough running turbo buick

[Burner]

Hey I'm a new member and owner a light blue stock 1987 turbo buick.Got it with 39k miles now have 60K.Was passing a car on the freeway felt the car hesitate a little. Got off the freeway and driving rough since, changed plugs, wires,coil(checked good on meter),MAF,O2.150 compression,turbo spins free cat not plugged ,hardly any back pressure on tail pipes,28 psi fuel pressure at idle 40 quick press of pedal.rough idle in park but a little bit pass idle engine smooths out.Friend with limited brought OTC said blms jumped to max quick other than that normal.Does not run better with cat off ,MAF,or with chip out.Please help this was my biggest fear owning one.Used to working on BB chevelles.

 

[87NAT]

Fuel pressure needs to be 42 +/- a few psi with the vacuum line off at idle.

 

[Burner]

Thanks gonna try it.

 

[Burner]

Sorry to bother you but the fuel pressure is 42lbs. with vac line off.Vac is 15.After reading other posts I changed the ignition module(AC DELCO)and still no help.Also the car won't idle keeps stalling.

 

[bmackinnon]

said blms jumped to max quick

Please explain this a little further... blms jumping up (to max = 160) indicates the car is bad lean and the ecm is adding fuel for all it's worth trying to maintain the AF ratio... could be a dying fuel pump, clogged filter, gummed up injectors... among other things. Need to temporarily hook up a fp gage with a hose that you can tape to the windshield and verify the fuel pressure is rising in a 1:1 ratio (pound for pound) with boost. Don't run the car hard at all with this condition as it can easily cause a blown head gasket. Need more time with the scan tool!

 

[asd60303]

I'm gonna say it's a fuel pump going south.

 

[Burner]

Thank you for the input,changed the filter first same thing.We had taped pressure gage to windshield and even though the car won't go fast enough to boost, the pressure goes up to 41+-. Would that rule out the fuel pump? My TR friend said the fuel pump sounds really quiet and seems to be the original.How do I check injectors for faulty or gummed up ones?Would injector cleaner in the tank or on the rail help or work?

 

[Burner]

Thank you for your time about the pump.Called TR shops and venders and first guy I talked to said if that is the original pump it is shot.My question is with good pressure could the pump still be bad

 

[bmackinnon]

If the pump is building/maintaining pressure, then that isn't the problem... Saw that you changed the maf.... where did you get the replacement? Generic big-box stores (oreilly, autozone, etc.) sell a replacement maf, but the calibration on them is usually total crap, and many times it takes 2, 3, or even more of their 'new' mafs to find one that works correctly. See if you can get your hands on that scan tool again and monitor the maf to see what kind of numbers it's delivering... should be 4-6 g/s idling, and rise smoothly as you start to put some load on it/accelerate. If the maf calibration is way off, then the ecm will miscalculate the fuel delivery (injector 'on' time) and then the mixture will be way off, causing the blms to be way off as the ecm is trying to compensate for it's 'own' mistake.... that would be the next thing I look at.... don't panic or fret, you/we'll get it figured out.... :wink: If the maf checks out, the next thing to look at is the ignition module...

 

[Burner]

Picked up rebuilt AC DELCO MAF unit from local parts store.Bought and installed ignition module same place AC also with no change. I'm going to check maf #s next.Seriously I might have to get mutiple units before a good one comes along?Could not see owning one of these cars without this great site!!! THANKS

 

[bmackinnon]

hmmmm.... yes, verify maf numbers..... OK.... here's a shot.... get your screwdriver out, and make DOUBLE/TRIPLE SURE all the hoses from the turbo to intercooler, i/c to up-pipe, and up-pipe to throttle body are tight/intact and haven't slipped off when you got on it to pass the car on the freeway... this will cause a vac leak, high blm, rough idle, etc... exactly as you describe... easy check... and you'd be amazed how many times this has stumped people before.... while your at it, check the turbo inlet/maf outlet connections as well... :wink:

 

[1quick6]

hmmmm.... yes, verify maf numbers..... OK.... here's a shot.... get your screwdriver out, and make DOUBLE/TRIPLE SURE all the hoses from the turbo to intercooler, i/c to up-pipe, and up-pipe to throttle body are tight/intact and haven't slipped off when you got on it to pass the car on the freeway... this will cause a vac leak, high blm, rough idle, etc... exactly as you describe... easy check... and you'd be amazed how many times this has stumped people before.... while your at it, check the turbo inlet/maf outlet connections as well... :wink:

Have to agree here. I've been caught by this before. The up-pipe hose had slipped off underneath and it wasn't visible. I didn't initially feel it with my fingers on first check.

 

[Burner]

All clamps and hoses are secure.Changed original hoses and clamps when I bought the car.Checked the hoses the day after this happened and this morning.Will my friends OTC be able to check the maf numbers or would it take a scanmaster? Never saw or used one but am more than willing to learn!!Need to get back to the quiet fast instead of the obnoxious load fast. Thanks for the info and this great site and members!!!My neighbors love this TR and also want it back on the road ASAP for the piece and quiet!!!

 

[kingots2004]

check for vac leaks everywhere and dont forget that little plug thats under the intake. i have blown the hose off that before also. also i have got new plugs that did not fix the problem tookem out and replaced them with another set and it cleared up.

 

[Burner]

Would the egr valve or the egr vac valve control cause the bad idle?Where is that small plug under the intake?

 

[kingots2004]

yes it could. look on the pass side down in between the intake. there is proably a vac hose comin off your vac block runnin down 2 it

 

[Burner]

Are the vac lines the three from the wastegate solenoid?If yes they are on.On the egr subject would that cause the no power issue also or just a bad idle?

 

[bmackinnon]

The OTC should be able to display the maf output... scanmaster would be nice... and you need one anyway...

To check the egr valve itself, just reach behind the round black cover with the engine running and manually push in (well, pull out, reach behind it and pull towards you) on the egr actuator diaphram.... engine should stumble badly, maybe even die... careful, don't burn yourself doing it.... it gets hot there.... if it stumbles badly, then you can surmise that the egr valve is sealing....

one quick way to check for a vac line leak is to pull the vac block off the top of the plenum, and put a cheap nitrile/latex rubber glove under it to seal it off there, and bolt it back down on top of the glove... start the car and see if that does anything....

Keep the faith... we'll find the culprit!!

 

[bmackinnon]

Check to make sure the cam sensor is tight/hasn't moved, and the cap is tight (2 screws) and not cracked as well.... just make sure you can't turn the cam sensor like you would turn a distributer with a loose hold down.... don't think this would be it, but give it a look....

Get under there and verify the crank sensor is tight and the crank sensor gap with the interupter ring looks logical.... I forget the actual spec... .020? .030?, but cut off a strip of plastic 2 liter soda bottle and see if that will slip in the gap... that's real close... and what many use to set the gap...

Also, make sure the harmonic balance bolt hasn't backed off... it happens ALOT for some reason... torque spec is ~215 ft-lbs... if it comes loose, it hoses up the crank sensor gap, and can ruin the crank snout from wiggling around... You have to take the pulley off to check the torque, but for your purposes, just pop the belt loose and get down there and pull and yank every which way on the pulley/balancer to make sure it won't move around..

Hmmmm.... Gotta' think about this some more... check all the above for prudence.... :wink:

 

[bmackinnon]

yes it could. look on the pass side down in between the intake. there is proably a vac hose comin off your vac block runnin down 2 it

The egr is on the driver side, rear... big round black covered thing.... the pcv is on the pass side down in the intake floor.... hoses from the vac block on top of the plenum run to both...