sputtering, bucking and cutting out...need some help

Zach L.

Member
Joined
Jan 31, 2017
Been working on the turbo t (mostly stock scanmaster,ta49,42lbinjectors,3"piping/maf,walbropump, TTchip..etc...) and driving it quite a lot lately, the car has always had its little gremlins like a hesitation to boost and a slight rough idle but a couple weeks back it sat undriven for a couple days and has never ran right since. It started with a real erratic idle on startup with the car trying to stall....went away with time but in the last week each time I drove the car about 10 minutes into the drive the car would buck hard and sputter and cut out under any type of load even low rpms... Now it will basically do this all the time and is undriveable...after looking through the forums and trying to find a solution i went through the obvious, coil pack tested fine plug wires did too and seem to be ok...fuel pressure is healthy and shoots up to 43psi line off. Plugs looked fine...maybe a bit lean but nothing major. checked for vacuum leaks and have none. fuel filter is new and car shows no real signs of fuel starvation. scan master shows nothing to abnormal just erratic IAC numbers upon warmup. the maf and translator are not too old and seemed fine but i cleaned maf and reinstalled anyways (also pulled it when car was idling and it did not help a thing).
So this morning i make it about 8 minutes and the car starts cutting out and bucking again...I slow way down pull over and unplug the cam sensor... lo and behold the car runs beautifully in batch fire (the best it has in months). So I limp the car home later in batch fire and decide to remove the caspers led cam sensor cap and inspect. The cap is about a year old and showed no signs of wear other than being dirty, wiped it off and inspected cam sensor ring and it had very minimal play almost none, it looked fine...So i bolt it all back up adjust the cap and start it up.(led is on while it runs) Worse than ever terrible idle and its bucking and sputtering all the way down the street, had to unplug the cam sensor just to get it home... I am lost as to what my next move should be. Any ideas? Did i miss something? and how long is it safe to run the car in batch fire...?
 
I just figure out a similar problem with my car. Check the crank pulley bolt. Mine was loose and the pulley was Wobbling just enough to hit the crank sensor to make it buck and surge and back fire
 
I just figure out a similar problem with my car. Check the crank pulley bolt. Mine was loose and the pulley was Wobbling just enough to hit the crank sensor to make it buck and surge and back fire


Thanks I will try and get to that in the next couple days...and look it over. I'd have to remove the IC and get a breaker bar in correct?
 
Thanks I will try and get to that in the next couple days...and look it over. I'd have to remove the IC and get a breaker bar in correct?

Yea and remove the little fan! The bolt has to be torque to 219ftlb
 
Also take a look at your cam sensor, take off the plastic cap and see if the metal cup is moving around on you, there is a little tab that keeps it in place, the tabs break and the cup turns
 
^^^^^ What Rick said.
Also, you said you checked the cam sensor and found, "and it had very minimal play almost none, it looked fine". Was the play vertical, or rotational? Vertical is the endplay between the gear and the base of the hsg. Rotational can be as mentioned, the drive tang on the ring is broke, screw is loose, or both.
 
^^^^^ What Rick said.
Also, you said you checked the cam sensor and found, "and it had very minimal play almost none, it looked fine". Was the play vertical, or rotational? Vertical is the endplay between the gear and the base of the hsg. Rotational can be as mentioned, the drive tang on the ring is broke, screw is loose, or both.

maybe slight rotational play but nothing really and screw wasn't loose... I'm going to start hunting for a stock cap.. is it fair to narrow this issue down to crank or cam sensor since its runs fine in batch fire? Does it hurt the car to drive around (slowly) in batch fire (have heard mixed opinions on this)?
 
It's fine to drive in batch fire. No worries there.

In my experience, if the crank sensor was flaky, the motor would die when the cam sensor is unplugged.

Good luck finding a cap. They are discontinued and there is no alternative. However you can still purchase a complete new sensor.

Start a thread for a cap in the parts wanted section and say a prayer.
 
It's fine to drive in batch fire. No worries there.

In my experience, if the crank sensor was flaky, the motor would die when the cam sensor is unplugged.

Good luck finding a cap. They are discontinued and there is no alternative. However you can still purchase a complete new sensor.

Start a thread for a cap in the parts wanted section and say a prayer.


thanks for the advice. And that is what i originally thought too... is it even worth messing with the crank sensor at this point? I can tighten the crank pulley bolt if its loose i guess but i think the issue is the cam sensor...wish me luck hunting for a cap!
 
ok checking that too, time to get the wrench and the 1-1/8th socket .... going to hunt for an oe style cam sensor cap also
I have a couple of brand new cam sensors if you want a complete assembly. $150 plus shipping. I'm headed out of town and won't be back until next Wednesday. If you haven't found one by then and are interested in one give me a shout.
 
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