87 Turbo T, high idle/driving hesitation problems/stumped????

[Ed Salsbury]

Hi Guys,
Appreciate the forum, great job!
Man, I'm stumped and frustrated, need some help, as I'm only backyard mechanic, if that......
I recently bought 87 Turbo T, 135K, Greedy Blow off, car had sat for 8 months, w/ 1/4 - 1/2 tank gas, started by previous owner only occasionally, no dash idiot lights, just washer fluid, and occasional brake lights, rpm gauge stuck mid way, boost gauge started working just now and seems fine

My problem (s), the idle is pretty high, and car has bad hesitation after acceleration and let off, must feather pedal or WOT to bring it back up, so....

This morning I changed all the plugs CR-43TS .032gap, (the pass side one by firewall was a MFer, dont know when that was last changed), new 8mm silicone wires, can of Berrymans B12, 10 gals new gas. So far after driving around town for 90 minutes and many WOT bursts, seems to be better, but still there, car will idle fine, although still high, and while parked will bring rpm's up instantly, no problem while in neutral, car accelerates at WOT like crazy with hard 2nd gear chirps, but again, after leveling acceleration off, and lightly touching it again, man, bad hesitation with occasional popping. I disconnected MAF and started it up, took test ride, no change, still same high idle and hesitation, but WOT is great.
I don't want to be a parts buyer, but thinking of fuel filter, new MAF, new coil pack??

Any help is greatly appreciated, thank you in advance

Ed

 

[salvageV6]

Check the chip see what you have in it.

Fuel filter is a good idea, MAF maybe, coil pack probably no if it runs ok WOT.

A scanmaster is a must as well to see what's going on with it, I wouldn't be going WOT without some more info.

Water temps., oil pressure, volts, fuel pump, etc. etc. etc.

 

[John Larkin]

High idle is usually compensating for something else. Go to gnttype.org and look in the maintenance section to set the idle air control (IAC). I would also be suspicious of the throttle position sensor (TPS) having a dead spot. If you can get a voltmeter, back probe the blue and black wires, moving the throttle arm smoothly through it's range, key on engine off. Watch for voltage drop outs or dead spots. Also having the TPS set properly is important as well. That is also on gnttype.org.

 

[Ed Salsbury]

High idle is usually compensating for something else. Go to gnttype.org and look in the maintenance section to set the idle air control (IAC). I would also be suspicious of the throttle position sensor (TPS) having a dead spot. If you can get a voltmeter, back probe the blue and black wires, moving the throttle arm smoothly through it's range, key on engine off. Watch for voltage drop outs or dead spots. Also having the TPS set properly is important as well. That is also on gnttype.org.

Thank you John, will check it out
Ed

 

[Ed Salsbury]

Check the chip see what you have in it.

Fuel filter is a good idea, MAF maybe, coil pack probably no if it runs ok WOT.

A scanmaster is a must as well to see what's going on with it, I wouldn't be going WOT without some more info.

Water temps., oil pressure, volts, fuel pump, etc. etc. etc.

Check the chip see what you have in it.

Fuel filter is a good idea, MAF maybe, coil pack probably no if it runs ok WOT.

A scanmaster is a must as well to see what's going on with it, I wouldn't be going WOT without some more info.

Water temps., oil pressure, volts, fuel pump, etc. etc. etc.

Thank you, maybe I'll install a new fuel filter next, probably a stupid question, but would a ref repair facility be able to use their diagnostic equip instead of me buying a $280 Scanmaster? Or is that just a must have with these cars?
Ed

 

[Ed Salsbury]

Thank you, maybe I'll install a new fuel filter next, probably a stupid question, but would a ref repair facility be able to use their diagnostic equip instead of me buying a $280 Scanmaster? Or is that just a must have with these cars?
Ed

"Regular repair facility/garage"

 

[Chuck Leeper]

Scanmaster is a necessity...Or, you could spend a grand, throw parts at it, and still not fix it!
While you are at it, check the fuel psi, all vac connections, clean the MAF, check for vac leaks, clean the t/b, clean the IAC.....Yadda, yadda.

 

[TurboDave]

Scanmaster is absolutely required IMHO, for proper troubleshooting, otherwise everybody is just throwing out guesses.
You've got to have data to properly troubleshoot any issues that pop up.

 

[ITSAV6]

Your issues could be caused by several things. Bad or mis-adjusted tps will cause high idle, tip in stumble, IAC counts wrong , injectors might need good cleaning could all be issues. A local GN bud just has similar issues. Got him to get a scan setup for his laptop http://www.reddevilriver.com/aldl.html Got it off ebay for $59 TunerPro is a free download and you can view all your sensors on your laptop like analog gauges. You can even us android setup and use bluetooth to android fone or tablet. His tps was bad.
Being able to see what's going on is essential!

 

[bpman1234]

YES I WOULD FIRST CHECH FOR VAC LEAKS.PVC VAC BLOCK ON TOP OF THROTTLE BODY.

 

[ITSAV6]

YES I WOULD FIRST CHECH FOR VAC LEAKS.PVC VAC BLOCK ON TOP OF THROTTLE BODY.

Great idea also. I replaces a LOT of vac line that were cracked. The silicone lines in metric sizes fit snugger. Vac gauge helps too.

 

[bpman1234]

Did you reset ecm? after you replace all those lines

 

[TRICKSIXPA]

Post up you location might just be better to go visit someone local that knows their shit!


Sent from my iPhone using Tapatalk

 

[ITSAV6]

Did you reset ecm? after you replace all those lines

No I didn't. Was working idle issues and it helped a lot.

 

[Ed Salsbury]

Thank you all
Yeah, I've got to find a local guy that knows these cars. I dont have a scanmaster and dont want to keep throwing parts at it. So far full tank new gas, two cans Berrymans B12, new plugs, wires, cleaned MAF, ordered air filter, have not replaced fuel filter or O2 Sensor yet. It is running better , will idle and rev up fine while in neutral, and accelerate strong after feathering pedal once it catches after stumbling, sputting. Today, came in from test ride, parked it, revved it up a couple times while in park, (Not very high), and then all of a sudden it stalled out. Now refuses to start. Turns over and catches for a second and then dies out. I'm in Rockland MA 02339, if anyone knows a local for these. Thanks guys, this is bugging the #$%^ out of me, I'm just not that familiar with these cars. Any suggestions are welcome.

 

[GNRick]

If it runs the same with/without the MAF connected I think you found your problem. If you still have the factory MAF it might be time to upgrade. I recently had a new LT1 MAF only last a couple months.

 

[gunzandgearz]

Lightly tap on maf sensor with car running see if it changes anything, I personally think its in the Iac but hard to tell as its what is responsible for controlling idle for different scenarios such as cold start up and loading engine when ac is turned on. Hook up vacuum guage and report back with readings, might have a few different things going on.

 

[Ed Salsbury]

If it runs the same with/without the MAF connected I think you found your problem. If you still have the factory MAF it might be time to upgrade. I recently had a new LT1 MAF only last a couple months.

Thanks GunsGearz, I think I'll replace it along with the fuel filter, any MAF suggestions or just a run of the mill one?

 

[Ed Salsbury]

If it runs the same with/without the MAF connected I think you found your problem. If you still have the factory MAF it might be time to upgrade. I recently had a new LT1 MAF only last a couple months.

Thanks GNRick, Yep, I think I'll replace the MAF, fuel filter, and clean up the IAC, Ed

 

[GNRick]

I assume you are running the stock MAF? Check out some options on full Throttle's website. Search for translator.