Stuttering at hwy speeds still

[blackbuick87]

A couple weeks ago I posted about this problem, where my car surges and stutters at 70mph and above. I installed a new O2 sensor since my other one had been exposed to race gas but it is still there.

Its REALLY annoying, because I cant accelerate in overdrive. With the converter locked, if I give it a little more gas to speed up to 80, my boost starts to fluctuate between 0-5psi, the car has very little power, and it shudders slightly. If I give it more gas it goes no where. I have to let off the gas completely, then step on it and it takes off normally. I know it sounds lean, but I dont see how unless I have a faulty Thrasher (running a T-97).

It will also do it in drive at about 50mph, so its not the tranny or converter I dont believe. Does the T-97 have a screwed up fuel curve? It is fine at 20psi and alky @ WOT

 

[Brian Mc]

I'm still having a similar condition, a fishbite condition from converter lockup at 45 mph up to ~70. The only things i haven't replaced yet arre injectors, ecm, and module. I don't think any of these will fix it though. I'm running a Red 93 chip.

 

[blackbuick87]

ttt

 

[blackbuick87]

tttttttt

 

[325DR]

Once the car is started and running, disconnect the cam sensor and go for a drive on the highway at the speeds that the problem is happening at. Post back after you try that.

Have you tried a new coil or module?

 

[Eric Stage I]

Bob, you may not have a choice but to try and record this happening on a scan tool. Have you tried a different chip altogether, just to rule it out? What happens to your O2's when it happens?

Eric

 

[Sinful6]

Sounds like an ignition problem..., I would look at your sparkplugs...

 

[blackbuick87]

I dont think it is ignition related, it doesnt pop or miss, its fine at WOT, and I have a new coil pack, module, plugs and wires.

Ufortunately I just got these injectors so I dont have any other chips yet. I want a race chip anyways so I might go ahead and get one.

Eric I dont have it captured on turbolink, but what should I look for? I wish I had a boost sensing harness so I could capture the boost going crazy from 0-5psi. It just feels lean. I could crank the FP up but that is just a bandaid

 

[Brian Mc]

I tried cranking the fuel pressure up to 47 lbs and it didn't get rid of it.

 

[325DR]

blackbuick87,

Did you try driving it with the cam sensor disconnected at the speeds you are having the problem?

 

[blackbuick87]

Originally posted by AintGoinSlo
blackbuick87,

Did you try driving it with the cam sensor disconnected at the speeds you are having the problem?

No I havent given it a try yet as I have not driven the car in a few days. How would tha cam sensor cause a problem at cruise but not WOT?

 

[GiveUp]

FWIW, I'll let you know my car did the same thing (course it would happen down low to... (started at 35mph sometimes). I replaced a butt load of stuff... Ended up being the Cam sensor cap. I would really try AintGoinSlo's suggestion. It isn't hard to get to and real easy to try. Has something to do with the way the ECM controls fuel. At WOT I quess it sprays so much/fast it causes the car to run normal, but a less than WOT it uses the cam as a reference for when to pulse?!?! It's been awhile.. can't remeber how it was explained to me. I know someone else with more grey matter will explain it better.

 

[Brian Mc]

I'm going to try this tonight as well.

 

[Brian Mc]

Ok, blackbuick87 definitely try the cam sensor. I came home and backed the car out and started, disconnected sensor after it started. I drove it, and the stutter is gone. Does this sound like a bad sensor or a sensor that is adjusted wrong? I did the adjustment process without a cam sensor tool, and i probably did it wrong. I just finished putting the engine back in the car and the cam sensor is knocking because it's not shimmed right. It did it before too when the sensor wasn't knocking. I suppose i should shim it right and readjust it. Any input on adjustment wouyld help.

 

[arista5]

mine did what appears to be the same thing, disconnected the cam sensor, and was like brand new, swapped the sensor and all was well

 

[325DR]

Originally posted by arista5
mine did what appears to be the same thing, disconnected the cam sensor, and was like brand new, swapped the sensor and all was well

arista5,
Did you just swap the cap? Or the whole sensor w/drive?

 

[arista5]

i was getting cam sensors complete for the prices of just the caps, so i changed the whole unit

 

[GiveUp]

In my case it was just the cap. To be specific, the ground wire was intermittent. Glad to hear a happy TR owner again. hehehe I had my car at 3 different places and every bloody mech. wanted to charge me 2 hours labor and than say it’s the MAF and they are discontinued.....

 

[blackbuick87]

I ordered a new cap and timing tool from Caspers. My question is if I just replace the cap I dont need to reset the sensor right?

I will probably check the sensor alignment anyways, but I want to be sure.

Thanks

 

[325DR]

Originally posted by blackbuick87
I ordered a new cap and timing tool from Caspers. My question is if I just replace the cap I dont need to reset the sensor right?

I will probably check the sensor alignment anyways, but I want to be sure.

Thanks

You are correct. The sensor does not need to be re-adjusted if you are only replacing the cap.