sr cutting out when cruising? loss of power , kicks back in

[zaquanh]

would really like to figure this out , think my car would be alot better

s13 sr



history on what ive done ,

changed out o2 sensor ,
changed out coolant temp sensor
taken off intake mani and cleaned it and iacv ,
with qtips , litterly from black to nice silver ,
changed fuel filter , new fuel pump
replaced gaskets ,
replaced plugs
checked 2 mafs. sr maf and ka maf , both work
not new to sr's , have the right plugs , gapped right as well ,

havnt checked timing with a gun , but its pretty close

no circ ssqv ,

ran seafoam


hove not ben able to check or replace tps
dont know shit about knock sensors
have not checked codes on ecu
have an exaust leave from turbo to dp


heres what happens

this happens in all gears

start out in first floor it , hit 15 lbs , can go through all gears and hit boost perfectly fine

when im driving normal , ie: just cruising , in any gear , around 3k or 2k right about at 0 boost or a little below and a little after ,

car just loses power can floor it almost like nothing a few seconds later or if i shift , power kicks back in like a 2 step , and BOOM full power hauling ass

checked almost everything i can think , it always does this if im cruising , its not a boost leak or a vacuum , i can hit boost and hold it at 15 lbs like nothing , can do a burn out , but if i am cruising say 55 mph or 20mph or 80 mph , it cuts out then randomly i get all my power back

[ultimateirving]

Why haven't u checked ecu for codes ? It's the easiest thing you can do to self diagnose. Sad people start trying all this other shit without checking that first.

Start there. Then verify you have the tps correctly set, with the ign off and at idle

[stylo1]

Check all grounds, make sure they are grounded to the chassis, and sand the paint beore grounding. also check tps timing. i had a similar issue

[Jtuned_andy]

TPS will cause a distinct dead spot in your rpms. i just had one at 2k-3k power drop

with the plug still clipped and the ignition to on but not running, use your volt meter to measure the middle wire of TPS to + and - wire to chassis ground. should be .45v at closed and 5v open throttle.

rotate the pulley with the test leads connected and make sure the numbers dont jump around indicating a bad tps. voltage should increase steady from .45 to 5 volts

[WaWhiteS13]

With it idling pop the hood and just start jiggling wires around to see if anything changes. Had a very similar issue with power cutting out when just cruising and flooring it then it would all the sudden come back. You might think its all ok until you move a wire just right, my MAF wires ended up being loose at the MAF plug and after fixing no problems after that. .02c

[zaquanh]

Why haven't u checked ecu for codes ? It's the easiest thing you can do to self diagnose. Sad people start trying all this other shit without checking that first.

Start there. Then verify you have the tps correctly set, with the ign off and at idle

because its call process of elimination and i dont have a volt meter even if the tps was off

[zaquanh]

TPS will cause a distinct dead spot in your rpms. i just had one at 2k-3k power drop

with the plug still clipped and the ignition to on but not running, use your volt meter to measure the middle wire of TPS to + and - wire to chassis ground. should be .45v at closed and 5v open throttle.

rotate the pulley with the test leads connected and make sure the numbers dont jump around indicating a bad tps. voltage should increase steady from .45 to 5 volts

thats what im thinking , how bad is it if i try and adjust it with out a volt meter , when you have dead spots does that mean the tps is off and i can adjust it . or gone and i should replace it


Check all grounds, make sure they are grounded to the chassis, and sand the paint beore grounding. also check tps timing. i had a similar issue

true

[cotbu]

Not bad, just not right, probably face the same symptoms. Those symptoms then trigger other events, like retarded timing. So after you adjust the tps to the proper range, .45v say's to the ecu, "hey the throttle is closed and you are idling". "Timing should be 15deg you only need this amount of that for this!"

Normally I don't see TPS's go bad, just adjusted wrong, the voltage would be .65v or so and at full throttle 5v. this range is out of spec. idle not stable. WOT is off the chart so at 85% throttle there's issues. .45v-4.125v is normal. or just under 5v
How are you supposed to adjust to a voltage, without being able to read the voltage?
After you do all that check for codes and verify timing.

[zaquanh]

Not bad, just not right, probably face the same symptoms. Those symptoms then trigger other events, like retarded timing. So after you adjust the tps to the proper range, .45v say's to the ecu, "hey the throttle is closed and you are idling". "Timing should be 15deg you only need this amount of that for this!"

Normally I don't see TPS's go bad, just adjusted wrong, the voltage would be .65v or so and at full throttle 5v. this range is out of spec. idle not stable. WOT is off the chart so at 85% throttle there's issues. .45v-4.125v is normal. or just under 5v
How are you supposed to adjust to a voltage, without being able to read the voltage?
After you do all that check for codes and verify timing.

cool will do , need to find my volt meter , keep loosing the leads then find one and not the other a year later lol

[zaquanh]

btw incase anyone else has this issue , i ended up grounding the TPS to the chassis ,

has the most perfect purr ive ever heard on a sr

[steve shadows]

So it was the TPS? Just making sure this solved the issue.

[zaquanh]

So it was the TPS? Just making sure this solved the issue.


yea , wasnt bad or anything , i think just a bad ground.

I ended up cutting the groud wire and grouding them to the chasis , i have a straight pipe ,

my car is super quiete , never hesitates any more , solid throttle all the way up. idle is smoth , timing isnt all over the place.