I did a quick log with winaldl on this 90 tbi I am putting back together. The biggest issue I am having at the moment is throttle response. I am only testing the car in park at the moment, still not road worthy yet. Throttle response upon quick stabs of the throttle yields delay and or back fire through the throttle body. I can slowly open the throttle and it responds fine. Timing is set at 2 degrees btdc with timing plug unplugged. I have reset the IAC based on the reset instructions, IAC seems fine. TPS has been tested, biggest problem with TPS is the lowest at idle Volts I can get it set at is 0.93 volts. Have tested 3 different TPS sensors and they all sit around the same voltage. Spark plugs and wires are new. I don't recall if the CTS was changed. The distributor, ICM, coil have not been replaced. I do not want to just buy parts, I want to determine what is causing the issue. Fuel pump and filter were just changed, fuel sits around 10psi and doesn't drop with throttle. I would appreciate if the tables I added here can be looked at and let me know if they are seeing problems in the data.

 

for what it is worth, idle is the last thing you tune.

you have to tune the ve table before anything else can be done.
everytime you change fueling, your idle is off.

get it running, and go drive it, thats the only way to make it work correctly

 

I am not necessarily tuning the car at the moment, just trying to track down why there is a throttle response issue. The car is all stock, no aftermarket upgrades. I should be able to leave the car in park, let it idle and stab the throttle with good throttle response and without it hesitating or backfiring.

 

I played with the timing, just by turning the distributor and listening to the motor and playing with the throttle at various turns of the distributor, not disconnecting the dist wire. I was able to get it to idle and improve throttle response but I do not know what the timing is now.

I tried setting it at o degrees and 2 degrees via the method of disconnecting the dist. wire and setting timing and then disconnecting the battery for a few minutes then reconnecting and starting the car. I was unable to get a good throttle response using this method, even though timing was set correctly.

 

for what its worth my 350 tbi will not run smooth at all at 0 or 2 degrees advanced. Runs best at 8 degrees advanced with the EST disconnected and obviously afterwards.

May be worth bumping that base timing?

 

Looks like your MAP is reading atmospheric? Verify that its connected to the TBI and at the unit.

Your rpm/map graph, is that showing TPS? if it is I would check your TPS. Pull it and with key on and winaldl connected run it through its sweep while data recording. For whats its worth may be worth downloading TunerPro RT and running some logs there. You get visuals which aid in troubleshooting.

I'd start there.

 

Thank you, I will look at the MAP. yes it is connected to the throttle body, but cannot confirm condition or age of MAP itself.

Are you saying for the TPS, remove the unit from the TBI unit manual run it through its ranges and see what the log shows? just want to be sure.

 

yeah at idle it should be around 25 Kpa. The one screen shows idling at atmospheric pressure (103 Kpa). That will throw fuel trims off for sure. Or obviously check for massive vacuum leaks.

 

Correct. .9 something on three different TPS’, I’d also check the minimum idle screw. Should be around .64 volts. Perhaps someone cranked it in?? The idle set screw is set when the IAC shows 10 - 20 counts at idle (575 rpm).

 

When I tested the various TPS sensors, I did so with a volt meter with the sensor off the throttle body. None of them read in that range of .54-.64, all read close to 1v. I will add that I had to splice in the correct connector for the TPS for the throttle body I have. All the wires were tested to determine the correct wiring orientation. The wiring harness I found for the car is a 1991 tbi harness I believe but the TBI motor is from the original car which is a 90 which had a different tps sensor.

 

Any chance you can send pic of the splices made? Perhaps you have a high enough voltage drop due to a bad connection?

 

I can take a picture of the splices. I was careful to attach the wires securely, solder them and wrap them.

 

What does a pulse reference mean and If I stab the throttle I get a rich flag, but I would think that is normal. Throttle is still laggy with quick stabs of the throttle but it doesnt backfire or shut down, just takes a second or two for it to respond and rev.

I also notice that the temp gauge in the car will climb to almost 250, fan doesnt come on (Fan has been tested and does work). The data log with winaldl say the temp is 208 and if I use an infrared heat gun on the thermostat housing its around 195. Can the temp gauge be that far off?

 

Bump, any thoughts?

 

Why is the map reading like that ? Major vacuum leak ?

 

Might be a faulty MAP sensor but I checked vacuum with a gauge and it’s right on point, around 20.

 

That should read 60-70kpa that’s extremely good vacuum

 

Am I looking at a faulty MAP sensor or vacuum hose to the MAP possibly?

 

🤷‍♂️ what your looking at

 

I’m not looking at anything right now tehcnically but more trying to troubleshoot the high MAP values. Vacuum is good with a vacuum gauge at idle, so either the MAP is bad or the vacuum hose going to MAP is bad(it’s a brand new line). Are there any other causes for the high MAP values and the TPS voltage that doesn’t sit below .93 volts? Wiring?

 

You could physically check the vacuum at the map hose , if 20hg the reading will be around 70kpa. The reading your getting 103kpa is around 3-4k elevation with no vacuum to the map. I’d resolve the map issue then look at iac steps. Someone could have messed with the idle stop screw. I turn that would effect tps voltage.

 

Noticed your iat looks like it’s unplugged

 

No idle air temp hooked up at this time.

 

intake air temperature sensor

 

That’s what I meant, IAT is not hooked up.