I've taken a 1990 Corvette from a pile of parts to at least running.

So, I got it running, But as soon as it got running, the engine was racing.

I got a timing light on it pretty quickly. I figured out I didn't quite get the distributor in correctly. After 4 times, I definitely have it set correctly.

I I went through the procedures to reset the TPI and Idle speed adjustment. But after figuring out quickly it was timing I shifted to adjusting the distributor.

It is nowhere near being right.

I'm going to stumble through this step by step.

1. Confirm no vacuum lines not connected.
2. All sensors connected.
3. Continue TPI/Idle speed adjustments.

Will doing the TPI/Idle adjustments fix a running rich issue? Or should I check additional items?

 

Did you disconnect the EST wire before setting the timing at 6 degrees BTDC

 

if it was running you probably had the distributor in right. too much timing at idle is not a problem.

if it is running that rich, check the vac hose on the FPr, fuel pressure regulator, to see if it is leaking/spraying fuel into the plenum. the racing engine may be vac leak, all over the engine bay.

disconnect the TPS and the ecm will use the map sensor or a default value until you get it idling right.

 

Uh, No. But I have now.

I just cranked it and set it to 6 degrees.

BUT- In the minute it took to do this- my pipes are glowing HOT.

Passenger Side


Drivers Side

 

I replaced the FPR with a new one. I'll check, but the guage which is still connected id holding steady at 40 lbs.

I can disconnect the TPS easily enough.

So reset the timing again with:
1. EST Disconnected
2. TPS Disconnected
3. IAS Connected
3. Checking FPR for leak (better not be leaking)

 

I don't think there is a need to disconnect the tps. Have you checked your exhaust for restriction? If you have a temp gun, check the temp of your catalytic converters. One other possibility could be a leaking injector but if car runs somewhat smooth the injector is doubtful.

 

Another thing to check is if your timing is set correctly. I had my balancer slip a few years back and even though I thought I had it set properly it was off and retarded the timing enough that my engine ran very hot. Just another idea for you.

 

Basically 2 things make an engine run hot like that. Timing is off or the engine is runnning lean.

 

I checked it with the TPS disconnected. Still hot.

I don't know how, but I'll find out, on how to check the exhaust for restriction.

The Fuel Injectors are brand new from FIC.

 

Lean?

As in not enough fuel? I replaced the stock injectors that were in the basket when I bought the car.

There were 2 seperate MAP sensors in the box. Maybe I put on a broken one?

 

Make sure the timing is set correctly. Disconnect the esc wire, set the timing to 6 degrees btdc. Connect the esc and see if the exhaust glows. A vacuum leak will also cause this.

 

rich will do that too...rich will do it WELL ! glow enough to signal someone

 

A poor mans way to test for a restriction is to use a Vacuum Gauge,

http://www.aa1car.com/library/exhaust_backpressure.htm

 

Short novela of the Car and what I've done.

1990 Corvette
I bought it taken apart for under $1000.

Condition:
The intake was taken off.
The fuel rail was loose.
The distributor was out.
The Fuel Pressure Regulator had been loosened and 1 bolt missing.
Shifter cable broken.

Previous owner said the car ran, but poorly based off of bad injectors, so he took it apart to fix but never finished it.

So what I have done:
Bought the Bosch injectors from FIS.
Put in a new Fuel pressure regulator, replaced all the bolts to it as one was missing.
Cleaned out all the old gas, cleaned up fuel pump, put in new filter.

I also did the following:
TBI bypass. I ran new hose directly from Water pump to fire wall. You would think it would be easy but when I started the car, a short hardline from the intake manifold on the passenger side (right near the distributor spewed water. I blocked it for now, but plan on running it to hose going into firewall.

I also removed the smog plumbing directly above the AC compressor. I removed the hard lines hooking up to the exhaust manifold on the driver and passenger side. They are still OPEN. I need to plug these holes.


I am sure I got the TDC and distributor dead on accurate. I use a timing light to time the engine. It is during these timing sessions that I note the exhaust manifolds glowing extremely hot. They are glowing cherry red in 30 seconds or so.

I've confirmed the timing. I suspect tuning may be cause for running lean or rich. Don't know which. I've done a partial TPS and Idle speed adjustment. But because the manifolds get so hot I have not done any TPS adjustments.

Do I need to make any adjustment to the computer based off of:
New Fuel Injectors
No EGR
Throttle Body Bypass

I just wanted to let anyone trying to assist know the whole story rather then trying to drag it out of me little by little.

 

Plug the open holes in the manifolds so there are no air leaks.
No EGR is worth 0 hp and only makes the factory tune wrong during light loads. It will also set a code for EGR failure.
You should not be doing an idle adjustment with the screw on throttle unless the previous owner played with it, you should find and fix the reason for wrong idle speed. Usually a vacuum leak or incorrect ignition timing.
You need to see if the timing marks are really correct for TDC it is not uncommon to have the outer ring slip, have someone put on the wrong damper of have the wrong pointer installed. Two ways to know for sure the first is to use a piston stop to find it and the other to just buy new ones or pull yours and compare to a new one. If the mark is in the wrong place from the outter ring slipping you can't set timing correctly.

At the end of the day you need at least 3 tools a factory service manual, a decent scan tool to monitor the efi system in real time rather than just read codes and a digital volt meter. With those things there are no mystery problems as the trouble shooting flow charts are very good in the FSM. It will also show all the hose routing and things like that the previous owner might have played with.

 

I think you can forget timing for now, as I said. if it were severly retarded it would not start and run, and will not cause red hot exhaust. as dahlgren said, fix the air leaks you have shown, also vac lks.

don't worry about ecm changes for what you have done, other than egr. it is running, which is a key here.

 

You;ve got MASSIVE leaks....imo
Clues...racing engine, all kinds of emissions ports open or semi d/c, no previous knowldge of this engine or what it should look like assembled...all adds up to leaks. Adjusting the idle is the ECMs job..not that of the screw.

Rule in engine tuning/combustion engineering:

cold combustion = hot exhaust
Hot exhaust = cold combustion ----->> open EGR passages do this. Air leaks will do the same.

Leak down test the fuel system. It should hold pressure 30+ psi for at least 1 hr then drop slowly. If it drops quick, the fuel is going somewhere. Find out where.
Air leaks.......? propane test? FIX all the d/c emissions stuff. The engine is tuned to have all that. The ECM is lost without the influence of much of that stuff. How its connected matters as well.

fuel that is not burned or the incorrect AFR will send excess into the exhaust that continues to burn. That is what causes the nice warm red glow...

does it rev sharply or hesitate/stumble?

to test exhaust restriction...simply pull o2 sensor and start. IF there is exhaust blowing out of the bung....the system is plugged. Max ex pressure is<3 psi...max.

 

I used to own a 924 Porsche, and the timing was 4 degrees after TDC. the cast iron exhaust used to glow bright enough in the daytime to see it. It was a lovely sight at night. I advanced the timing to 0 degrees, and it would start and run at idle and have plenty of acceleration, but pinged so bad it would not hardly move the car.
I suggest you get a new or good use harmonic balancr. That is where the timing mark is.

 

Conducting checks right now.

 

Definitely get plugs for the AIR line on the exhaust manifolds. IT could be that outside air is being drawn into the exhaust and helping to create a lean condition.

You can get NPT pipe plugs at Home Depot or Lowes. I think they are 1/2" NPT. I did that on my 87 when I removed the AIR system. Just use a little anti-seize on the threads so the plugs can be removed if needed later.