need help, 95 hardbody very sluggish/weak.

[upcominZ]

my 95 is acting up. sometimes its fine, sometimes not. No check engine light, no ecu codes stored. Problem is that sometimes when i give it more than 1/4 throttle, it just will not accelerate. no roughness or smoke, just wont accelerate. i changed the fuel filter twice and have 190ish in all cylinders. im leaning towards the tps, b/c it seems like it has to do with the amount of throttle you give it. up to about 1/4, it accels fine, after there is no acceleration, just sorta boggs. any help/suggestions is appreciated. thanks.

[Rev_D21]

Welcome to NICO, Sounds like a timing issue to me.

[Big-Bird]

The manual points to the following sources:

1) Incorrect Timing 2) Excessive distributor shaft play.3) Faulty or incorrect spark plug gaps4) Dirty air filter.5) Spark timing control system malfunction.6) Faulty ignition coil7-9) These are brakes and transmission fluid or clutch related issues.10) Clogged fuel filter. (Not likely since you already changed it)11) EGR system malfuntion.12) Crappy fuel, ie water or other foreign liquids mixed in.13) Uneven cylinder pressure. (Not likely since they all read high.)14) Air/vacuum line leak at the manifold or injectors.15) Clogged or dirty fuel injectors.

If the engine surges with the gas pedal pushed to the floor then you either have an intake leak somwhere or the fuel pump needs to be replaced.

A computer scan would help determine if the TPS was damaged.

[upcominZ]

I checked the timing. its right at about 15deg. at 17deg it pings and is at almost full advance. I also think its a timing issue. Could the distributer be bad? do they even go bad? the ecu scan doesnt come up with anything. I think its 5 or 6 on the list above.

[Rev_D21]

The dis. could very well be bad. You may also have a vacuum leak causing un-metered air to be entering the chambers.

[nismopu]

we recently had a similar issue come up over at blah-dee-blah.com and it turned out to be excessive play in the timing chain. I thought it was a STRETCH(pun intended) but it turned out to be the case. when was the last time you inspected yours?

[upcominZ]

i haven ´t check the chain. the mechanic said it might be the chain but i didn´t believe him. how difficult is it to change? i don´t remember it being excessivly loose. but, why is it that it only happens sometimes? sometimes its strong like it should, other times its weak.

i unplugged the tps and it didn´t get worse or better. i swapped out the maf and made no difference. didn´t run any worse. i will swap out the tps and see if that may be a problem. seems like it has to do with the amount of throttle i give it. it doesn´t respond after 1/4 throttle. just accelerates the same.

[nismopu]

leave the TPS on and measure the resistance between the two outside contacts on the TPS itself. The middle prong is what recieves 5 volts and isnt necessary for this test. If you cant measure any resistance at all then its probably bad and the ECu is being delayed until the other sensors come into play. The TPS in a manual vehicle is more or less an ON/OFF switch, only autos use a full sweeping POT style TPS. let us know what you find out. peace.

[upcominZ]

ok. what is the resistance i´m looking for? what is spec?

[nismopu]

ok. So, I owned myself. lol! Were actuallly looking for voltage not resistance. Should be 2.2ish at half throttle(45 degrees) and 4ish at full throttle.

BTW, is yours a dual plug TPS or single? This will determine where you place the probes. peace.