Chevy 7.4,Throtle postion sensor problem??

jcramphorn · 09-16-2010, 07:20 AM

Hi,

Have a 1995 7.4ltr RV thats been running rough for ages, thought it was the timing being set up wrong, but, just pluged it in to diagnostic and it ses 'throtle position sensor (TPS) to higher voltage'
Any one had this before?
is it another problem sending to much voltage to the TPS?
Or is it the TPS itself being faulty?
Am in the UK so not easy to get parts to just start replacing things
Thanks

Bert_64 · 09-16-2010, 08:19 AM

Should be 0.5volts at closed throttle. There is 2 torx screws on will allow for adjustment. Measure with the engine off and the ignition in the run position.

jcramphorn · 09-16-2010, 09:36 AM

thanks,, its running at 4.75volts with the engine running, il go and try it now with the engine off

tjwolf · 09-20-2010, 03:19 PM

If the TPS adjustment does not fix the problem look at the EGR valve. Had periodic missing and rough idle. Chased the plug wires, spark plugs, rotor, dist. cap, etc, to no avail.

Finally found a stuck/sticking EGR operator stem. Cleaned carbon off of the valve stem to get it running, then replaced it with new. Only two bolts and a vacuum line to check the operation. Once off of the engine, push the stem in and out to see if it operates freely.

Now the unit runs great!

Tom

InPursuit · 09-21-2010, 04:28 AM

the signal from/through the TPS device affects all sorts of things.
My main symptom was reluctant up-shifting from the auto transmission.

good to go now.

jcramphorn · 09-24-2010, 02:08 AM

Thanks

It was the TPS, got one from NAPA for $29. Put it on and instantly it transformed the engine, i first bought the Rv 3 years ago and now realise its had this problem the whole time!