Can someone please assist and tell me the correct specification for the voltage on the TPS signal wire? I have seen values from 0.525V to 0.54V. I have a 1990 stock L98 TPI and just fitted a new set of Bosch lll injectors. It's now blowing whitish smoke and exhaust smells of fuel. There are no engine fuel leaks. I then checked the TPS signal wire and it read 0.64 on a new voltage metre so it need adjustment.
Thanks in advance....Paul

 

Setting would be .54v +/- .075. A reading of .62v shouldn't cause your conditions. A vacuum leak could.
MAP has more to do with rich condition. White smoke after start up condensation which should disappear after 5 minutes or so or coolant.

 

Are the replacement injectors the exact same size as the stock ones? If they are larger, you will get a rich condition until the car goes into closed loop.

Have you checked your fuel pressure? Pulling the injectors could have disturbed the fuel pressure regulator. Is the vacuum line to the fuel pressure regulator properly connected?

Lastly, before adjusting your TPS sensor, you also need to attach a scan tool to be sure the IAC (idle air controller) counts are within specifications (should be around 20). If they are not, the throttle plate stop position may need adjustment, or as Kevova mentioned a vacuum leak could be present.

Does the rich fuel smell clear up when warmed up?

 

Tks for the responses. The Bosch lll injectors are 22 PSI which I understand is the same as the originals that I replaced and to GM spec. I purchased the Bosch llls from FIC who were recommended by other members. The exhaust fuel smell continues when warmed up. I'll double check the items suggested by u both and see what happens. I detached the TPS when I removed the throttle body for cleaning (with aerosol carby/throttle body cleaner) as I did not what any throttle body cleaner to contact the TPS. The TBI was pretty dirty. I did not remove the coolant cover under the TBI. I live in country Australia so Vette support is scarce.

 

Only use ac delco TPS!

the later l98s take the first value it sees and sets that as base. They are not adjustable so don’t fret.

What else have you changed? Injectors?

white smoke usually means coolant. Any ideas from where?

 

When did that start?

 

I think it was from 1990 when they went to Speed Density. Looking at Autozone, an 89 uses a TPS113 or Delco 213-905 and a 90 uses TPS132

 

Why smell when you can read? Hook up a scanner and see what the ECM thinks the O2 sensor voltage is and you can see if it is rich or lean. I don't care what you think. I care what the ECM thinks. I don't believe you can adjust the TPS. The older TPS (89 and earlier) has slots for the bolts so you can adjust it. The 90-91 does NOT so all you can do is slot it. HOWEVER, if you do, the ECM will see the startup voltage and assume it is baseline.

What coolant cover? You mean the IAC housing? Go ahead and remove it. Link up the coolant hose so you bypass the Throttle Body altogether. Also use new gaskets when installing. Take out the IAC and the IAC housing and the top plate of the TB. Flush all with brake cleaner. Spray a mist on the pintle of the IAC and GENTLY wipe it clean.

 

Sorry for the delay. Answers to some of the earlier member questions... My issues started because 1 of the original GM injectors failed, so I changed all 8. My Vette has 55K original miles. This was the 1st time the throttle body and plenium had been removed. After putting it back together with Bosch111s from FIC and all new gaskets, the issues I described earlier, then started. I had removed the TPS when I was cleaning the throttle body to ensure it remained dry.and one thing I later found out was the the TPS should not be removed. I then though part of my problems may have stem from from removing the TPS, so I checked the voltage. It read 0.625V when I should have read 0.54. I then found that the TPS is factory set so there is no adjustment on the 1990 model L98 TPI as pointed out by aklim. There is adjustment on earlier years. Kevova advised 0.625V should not cause my condition.
The only disconnections I made on the cooling system was to disconnect the inlet and outlet hoses connected to the coolant cover located under the throttle body itself so that I could remove the TB for cleaning. I did not remove the actual coolant cover; only the hoses. I did not disconnect the AIC I only disconnected the electrical connection to the IAC valve.
Unfortunately, I do not have access to a scanner so I cannot check the ECM reading for O2 voltage.
If my issue is coolant contamination, I do not know why or from where. The oil is normal. The plugs look normal and all similar. The rocker cover is not milky. The engine is idling smooth. I 'll do a compression test next.
Once I fix the current issues, I'll do the bypass as aklim suggested.
Can anyone recommend a good scanner for a 1990 L98 TPI stock Vette?. I'll have to import one from the U.S.
Paul

 

Why would the TPS not be removable?

Just join both of the hoses or I think someone has previously suggested a hose for the bypass. I'll look. You can still do the cleaning with the IAC removed if you want.

Can't hurt. Borrow a tester from Autozone

Sure, I'll see if I have a note somewhere about the hose required.

Look at http://www.1320electronics.com/products.html

 

Hey Paul
Here is a link to some info on different scanner options
https://www.corvetteforum.com/forums...1-scanner.html
I’ve used WinALDL and I made a cable for my 84. I think the guys with newer C4s prefer something like TunerProRT. I use TunerProRT now but I have changed my ECM over to an EBL Flash unit so I have no experience with it scanning a standard ECM. In the attached link someone mentions the mighty GM Tech 1 scanner. I remember when all the Holden dealers had them, I wonder what happened to them, they probably through them out.

 

To check rich/lean use Diagnostic Mode:
-use the paper clip in ALDL pins A&B
-start engine and let warm up
-watch the SES flash On/Off durations after in closed-loop
-if the A/F is ok the On & Off durations will be ~equal

Have you checked manifold vacuum, since you had the system open? Remember the little vac line under the TB and the larger one on starboard side.