Hi all, I have an 87 TA with 350 TPI. I was having an issue with the car losing power at 3000rpms when warm so following advice here I ordered a new FPR diaphragm (ACDelco) and while I was in there I replaced all the o-rings in the fuel rail, put in Delphi 22lb injectors from Southbay, new intake header gaskets, and I also ended up replacing the water pump because the old one was leaking from the weep hole. Before all this, the car would hold 43.5psi fuel pressure after priming for a good 10 mins after the key was shut off. The car used to idle beautifully with no issues except the 3000rpm problem.

Oh boy.

Following all this, here are the issues:

• Car will not idle. Starts up great, but will only run at 2k rpms with throttle depressed. Otherwise it dies.
• Water from exhaust. Not coolant, but what appears to be clean water (honestly, could just be because it's been stood for a few weeks).
• Radiator cap is smoking and hot, even before engine is up to temp. Concerned that I was given a serpentine (CCW) water pump instead of the v-belt one, though I checked the part code and it looks right.
• Fuel pressure drops to 20psi after priming and within 10 mins it is at zero.
• Smell of burning rubber while running (I thought this was a v-belt not tightened, but I checked all).

Yikes. I clamped the fuel return line and even tried a second FPR body and diaphragm. I can't see any fuel escaping from anywhere and I am struggling to believe that the fuel pump check valve has only just decided to go bad.

Checked resistance on all injectors, 16 ohms.

No sign that I have a leaking injector.

All vacuum hoses triple checked.

Help.

 

Ouch... I didn't see any of your old threads so I don't know what all led to you replacing injectors. However, I must ask... did you log any data or have a scan tool now?

* For your idle issue, I would be thinking it is either way rich or way lean. Here it would be good to see IAC counts, CTS reading, and 02 readings combined with BLMs. My guess is the ECM thinks you are lean and is adding fuel when you don't need it. Though, it is only a guess without data. There are a couple of things than can cause this.

Water from the exhaust may be condensation due to cold pipes or high humidity. My LT4 has chrome Corsa tips and anytime I start it up I see condensation on the outer lip for a bit. Volume of water is what is important here. I often get a little spray on the floor if I let it sit and idle to warm up in the garage... not puddles.

Radiator cap would have a hard time getting hot if the pump was not moving coolant. Obviously it is getting hot water from the engine to the radiator. Running excessively hot is can result from lean. What does the dummy gage on the dash read at that point?

For the fuel pressure, I have seen this situation and is not detrimental to operation. You could have had a spec of dust on the seat of the FPR that let's just enough pass. Unfortunately to confirm the injectors you would have to pull the rail up after priming and see if any leak. I have considered this before, it is just a lot of work. You can also find a spot on the feed side to block/crimp to isolate the rail/injectors/FPR

Are you seeing any smoke/steam while you are smelling the burnt rubber? Did you drop anything near the exhaust manifold, including any liquids? Are you sure there is not a wire harness, vacuum line, or spark plug wire/boot on or near the exhaust manifolds.


Wish I could be more help, but very difficult to diagnose issues like this and data is king. Hope one of those pointers helps.

 

I appreciate the response!

Can you point me to the correct scan tool? I found WINALDL but the site only lists TBI engines as supported - though my hope is that it'll also work for mine. I've got the parts needed to build the interface.

The reason for changing the injectors was that someone on the forums here advised it since this vehicle has very low miles and has essentially been parked up for the majority of its life. I needed to pull the fuel rail to deal with damaged security torx screws on the FPR, so while I was in there I installed Delphi 22lb injectors.

My assumption for now is that the smoking radiator cap and burning rubber smell is due to some kind of spilled fluid, so I'll worry about that later.

 

I made up a cable for WINALDL and it's receiving data but the program can't understand it - looks like other people are saying that the software has trouble with the ECU for this vehicle. I did remove the throttle body and cleaned it up well, and also tested the IAC.

I've not found this thread, and I have all the parts, so I will try that cable next: https://www.thirdgen.org/forums/diy-...able-help.html

 

Made a mk ii cable using a 5V FTDI, which is really simple: connect GND to pin A, and RX/TX to pin M, works great now with Winaldl. I went through the reset procedure for the IAC and now the car idles without stopping. Very lopey, so I tested the TPS and that is perfectly calibrated. I'm getting code 34/MAF air low. Will post updates when I manage to solve that!

 

What are you getting for MAF readings when the car is idling with the engine warmed up?

 

Well, once the car warms up it won't idle without a little throttle - and then it will only idle at 1000rpms+. So, engine warm and "idling" like that, I'm seeing 21.5g/s from the MAF. That is way out of spec, no? I thought it should be 4-7.

 

Forgot to say that this is with a 10K resistor between A and B - can't get readings otherwise.

 

After doing the IAC reset procedure (again), I can get the following logs with a 10K resistor, which causes a high idle:

Coolant temp: 178
RPM: 950
TPS: 0.55v
INT: 182
O2: 0.146
BLM: 156
MAF: 7.04

It will run OK like this but when I pull the 10K resistor the RPMs drop to 600 and it gets very lopey and occasionally backfires. Unfortunately with the resistor removed, I can't log.

 

That is odd, as lean as it’s looking I am curious if you have a vacuum leak somewhere in the TPI but you said you couldn’t hear or find any…that first MAF reading is high but at 1,000rpm might be within spec but the second one you shared is within spec

One time when I was doing work with the TPI removed and upon reassembly I had new gaskets for the front runner to intake manifold which I accidentally used the opposite sides( they will fit btw), that created a big enough vacuum leak the car would idle over a 1000rpm and could trigger such lean readings. Easy way to check is use smoke or throttle body cleaner in that area and it should flare up if not correct.

 

I will do a smoke test tomorrow and will report back - thanks!

 

The smoke is supposed to be better, it will really pull it in. My air leak there was large.

 

Made a home-made smoke machine (honestly only took 5 mins) and then 5 mins later found a couple of leaks. Minor leak on one vacuum line, major leak on intake runners - looks like even though I thought I had checked a bolt twice, it was still loose due to my socket getting stuck on the runners. Holy hell, started up first time and idled perfectly! THANK YOU for all the help!

During all this I found that the 9th injector was completely gummed up so I made a DIY injector cleaning rig and it now sprays perfectly. I might delete that at some point and update the ECM.

 

Glad I could help, at least you didn’t have to swap the gaskets like I did.

If you delete the 9th inj there is a nice delete kit on eBay, you can pull the whole thing without having to remove the plenum etc it’s very easy. I also got a new tune when I did that to delete 9th inj., have the fans come on at cooler temp to lower engine temps( with 180 t stat) and give the car a bit more kick and it worked out great.

 

Where did you get your tune from? I've just really started doing my research as I have not had the car very long.

The burning smell has gone - that was likely caused by the same thing causing the smoke around the radiator cap. Just me worrying about nothing.

 

Tunedperformance.org is his site and he is a member here and knows his stuff, good guy to deal with and many members here have used him.