Im not 100% sure what either look like. Its small and black. Arent check valves green or something? Maybe ill get off my *** and do some problem solving today, check some solenoids.

This hesitation issue is really throwing me through a loop. Im starting to think its a solenoid because the hesitation disappeared after changed a water sensor then came back after a month randomly. I hear they are prone to sticking open and can randomly start working and not working.

But I dont get why there is little to no hesitating at first but gets worse the more I drive (to the point where its undrivable/dies). Do solenoids get worse with heat/more driving?

 

Solenoids do tend to fail with heat. When testing them, it is advised to test them cold, then stick them in the oven and test them hot.

The MAP sensor should have a filter in line with the vacuum line. It is small and black in color.

You could also check your FPR solenoid. If that sticks and constantly has vacuum on it or no vacuum, then your fuel pressure can be all over the place.

Matt

 

Hey guys car still hesitates. Starts and idles great. Even drives very healthy for the first couple blocks. Usually starts hesitating while accelerating after a few blocks. Hesitation gets worse and worse the more I drive until the car literally wont drive, if i try to gas through the hesitation its very violent and will stall. Eventually the car will stall if I keep trying to drive.

Things ive done:

-Apexi Power fc
-non seq conversion
-deleted emmisions/installed block off plates
-New TPS and recalibrated perfectly
-New supra tt fuel pump
-rewired fuel pump
-new fuel filter
-new alternator
-new spark plugs
-new o2 sensor
-new water temp sensor
-good grounds
-good map sensor

Ive now been hunting down this hesitation issue for over 2 years..... Im ready to fix this thing.

 

I'd recommend getting a fuel pressure gauge. I suspect fuel delivery is the problem.

 

I've always felt it was a fuel delivery issue. According to the pfc the engine knocks a bit when it hesitates. I was kinda thinking fpr I'm just confused on why the issue would get worse the more I drive?

Just picked up a new battery and fuel Guage so lll go see what I can do.

Here is a little video of the hesitation:

https://www.dropbox.com/s/fym4azlmwk...60517.mp4?dl=0

Thanks for the help Fritz!

 

Talk to me about your fuel injectors.

 

They're stock, haven't tested them. Used to think it might be the secondaries but the car hesitates no matter if I'm heavy load or not after a few blocks(although it does get worse the more load there is). Then it stalls, thought the primaries would keep it running under low load.

Tested the fuel pressure and I'm getting just over 32 psi during idle.

 

I've actually never heard of a TPS sensor going bad...... What are the details on your wiring harness?

 

I've changed the tps a couple times. Ended up figuring out it was a wiring issue. The harness is a bit of a mess at the ecu, someone was splicing things and didn't do the best job, dunno what they did under there to be honest. That's where I found the tps wire disconnected. The harness is old and crispy as well.

 

After watching the vid I don't think it's the pump

I'd lean toward ignition especially since it's also possibly heat related. Have you replaced the leading coils yet.

 

My dad actually tested the ohm resistance on the coils over a year ago and it was fine. Mind you, we ended up figuring that issue out and this hesitation developed later on. I'll check them again, probably replace them guessing theyre original.

Would an igniter cause this issue as well?

 

Based on what you're telling me, I'd recommend replacing the engine harness asap with a known good one.

I had a piece of **** Rywire harness on my FD not too long ago and it cost me a motor.

OEM ftw in this case

 

so ive just replaced the coil packs, spark plugs(again), and wires. Buttoned up the engine and took it for a drive, drove beautifuly for much longer than usual (like 10 mins of spirited driving after it warmed up) then the hesitation came back.

I snapped a stud on the throttle body and that made me start considering boost leaks again. Has anyone had a boost leak with symptoms like this? (runs/idles great, after a while of spirited driving will hesitate and get worse to the point where the car wont drive)

Also been talking to a local mechanic that's worked on fd's, he said to check the crank sensors but ive read they don't go bad and I don't think im experiencing bad crank symptoms but im no expert.

Goodfella, definitely could use a new harness. However im gonna exhaust all other avenues before I dive into that project.

 

It's not a boost leak. If the issue is indeed the harness, all of the rest of this is a waste of time and money

In my experience if you have CAS issues, the car won't start up.

 

Well you got me looking for harnesses, any ideas of where to find a bare bones harness?? Im looking for a better than stock single turbo harness, hopefully someone around here still makes them. Im gonna go over the car and work out exactly what I need to run.

You really think the harness could be doing this after some driving? I figured the issue would happen random or all the time if it was a harness.

 

New ones run about $850 for an OEM harness and I believe a member named C Ludwig makes custom harness' as well.

Matt

 

Spoke to Ray Crowe yesterday, he's going to be selling them again here shortly for the 'Steal o' a Deal' price of $850 bones.

Ludwig is spoken highly of wrt his harnesses, he told me they run around $1000. Issue for some would probably be the wait time as they're custom made to order.