Hey guys, just imported my 2nd fd. its a 93 jdm type rz. cold air intake, catback exhaust, bov, and it has no precat stock.
The car bucks under acceleration. mostly 3/4 to wot. And on deceleration. It also idles around 1000-1100 rpm and misfires
or backfires (not bad and no abnormal smoke coming out of exhuast). The dash has both the coolant and oil dots, 4w abs,
and charge lights on. They shut off at higher rpm. Oil pressure reads mostly normal but falls flat regularly and randomly.
(didnt always have the dash light issues, they recently developed). Car also had an oil leak around turbo oil drain area.

So, I have replaced the tps sensor after fiddling with it forever because it would not go within spec range. My current
tps wont go into the acceptable volt range at wot, but it will with no throttle on both wires. The tps has to be tilted
completely closed to get the 2 values within spec. I tried cleaning it and still no dice. Any ideas?

I plan on replacing the alternator because it is dieing as well. Hopefully that will fix the dash light situation, I read that it should.
Also will be putting a fuel filter in tomorrow. Fluids have been changed, spark plugs are being ordered. What do you guys think about the oil pressure? Is it
related to the alternator being faulty or should i replace the sensor?

I put some rtv seal on the turbo oil drain pipe ends, they had no gaskets and I believe thats what was leaking. I'll have to
see when I get it back up and running properly.Been searching for hours and any help would be appreciated guys!!

 

I had the same symptoms as you with the bad alternator, so make sure to replace it. Also check your battery terminals to make sure they are clean and tight. The oil pressure gauge reading inconsistently is normal for our cars, as it is a problem with the factory oil pressure sender. As for the tps, last time I checked mine it was almost completely closed as well, and it is within spec.

 

Thanks man. Okay so the alternator was causing your bucking issues or just the dash light? I can get the tps in the closed throttle ranges .75-1.25 and .1-.7 .I cant get the wot reading 4.8-5.0 and 4.2-4.6. both values are over 10v.

 

Fuel filter replaced, still having bucking issues.

 

Boost leak?

 

Alternator and grounds

 

my friends FD just had problem with bucking under any excel.. map sensor went bad.. im no tech.. just a thought

 

Alright, I ordered an alternator and I'll check and see if the pressure sensor is still good. also going to try reseting the idle screws.

 

So I was swapping the alternator the other day and broke a couple vacuum lines. Checked under the uim and it looks like some lines have broken/fallen off. Non sequential conversion it is lol. Hopefully I'll have it back up and running in a week or 2. So guys, with all my mods and going non sequential, will I need a ebc or ecu, or should i be fine with all the resistors installed? I plan on porting my waste gate and keeping my main cat in for now.

 

you can stay sequential and upgrade your hoses to high temp silicone hoses.

I personally would stay sequential for the fun factor. =)

-AzEKnightz

 

I love the sequential system but im just wanting to get the car back on the road asap. I also plan on going single this winter so I'm not too worried about it.

 

If you want to get the car on the road asap, then it would be less trouble to just to fix the hoses than converting to non sequential.

 

qft

 

Shinrars2 is right. Just fix those hoses and be over with it ;-)

-AzEKnightz

 

Turbos are off, just gotta get everything ported and welded etc. Also figured out my dashpot was never being depressed on idle. So I'll take a look at it tomorrow and see if I can adjust it.

Hopefully one of these will have fixed my issues. Ill update this when the car is running. thanks guys!

 

I'm having similar issues but not as bad, so I'll be watching this thread.

 

So got the car all back together and driving. So ive done the non sequential mod. Got it down to about 6 vacuum lines. Removed all emissions and installed the block off plates. Installed resistors into the harness and non sequetial moded the manifold and turbos. Ive got my tps to read within its correct values as well.

Im still getting hesitation or stumbling issues at half throttle or more. it still doesnt decelerate very well either. Idle is better now after adjusting the idle screw and dashpot. Any ideas?

 

Your getting 10V out of your TPS sensor at WOT?
That's not right, can you check the input voltage to the TPS sensor? Should be the brown / white wire. There should be 5V on there, check if it isn't 12V.

 

What are your A/F numbers?

 

I got the tps to read within the right spec. I was driving the car a couple days ago and the hesitating got extremely bad. i was at about 1/8th throttle and the car was chugging really bad then shut off. It seem like a fuel issue to me or maybe even a clogged cat? I checked the fuel pump and it was only getting 8 volts. rewired it and now getting something like 14 volts but the car still cant accelerate. It idles extemely smooth now and free revs awesome. Just doesnt like to be under load.

 

I dont have a wideband installed.

 

You may have an extremely bad vacuum leak? Check the spark plugs.

 

Spark plugs are changed. I have about 7 vacuum lines that I just changed. What other vacuum leaks should I look for? The chugging gets worse as the car warms up.

 

Blown intake manifold gasket.

 

Would the issue get worse as the car warms up, if its a intake gasket? Its not the uim gasket and I'm really not wanting to pull the turbos and everything out to check the lim gasket.

Heres what I've done: fuel pump rewire, new fuel filter, tps adjustment, vacuum lines are all good.

Here whats wrong: car accelerates but chugs or hesitates (feels like someone letting off and pushing the gas pedal quickly) when cold and gets worse when warm. It also almost stalls if I shift out of gear in higher rpm.