Hello! I recently got a 94 VTEC Del sol and did an engine swap to a b18b1 from a b16a3. It is an OBD1 to OBD2 engine but we kept the obd1 harnesses and got a p75 obd1 ecu. The car is started and is driving.
I have a CEL for the TPS and I'm trying to fix this issue. I checked the TP signal and voltage going to it and it's getting 4.97V but only like 0.03v when checking the signal with the throttle closed. I thought the TPS was bad so I replaced it and it's doing the same thing... Any ideas?

Another issue I'm having is that the car will start to stutter or hesitate when accelerating after about 20-30 minutes of driving. During constant speed, its jerks every couple of seconds. And during idle, it fluctuates up and down like 200-250rpms. Sometimes it drops to like 200/300 rpm. Is this just a bad IACV? TPS issue?
Are these issues connected?

This is my first project car so im trying to do everything by myself but I'm at a loss here...I'm a little car dumb and learning.
Thanks guys!

 

Your problems are related to the TPS not being calibrated.

Have you tried to calibrate the TPS yet?

Connect the negative terminal lead on your multimeter to the battery ground. Connect the positive meter lead to the red signal wire and check the voltage. Turn the TPS until you get a reading of 0.5v DC, and then tighten the screws. Verify that you are getting 0.5v when the TPS is closed and 4.5v when it is open.
Honda Civic: How to Replace and Calibrate TPS | Honda-tech

Once TPS is fixed set the ignition timing to spec and go from there.

 

I attempted to Calibrate it. I checked the voltage when i put it in and it was getting 0.03v even after i turned it a little bit... this is with two different TPSs. I feel like the wiring for that red signal wire is bad somewhere or im just stupid and idk what im doing
When we installed the b18b1, we made sure the timing was correct and was at TDS. Is this not what youre talking about? I know you can also turn the distributor and grab a timing light?

 

Yes use a timing light to set ignition timing.

What does it read when the TPS is WOT?

Make sure the volt meter is set to Ohm

Make sure you insert the tab of the TPS into the slot in the throttle body.

 

Oh, it's supposed to be set to Ohm..? well that would explain a lot... I haven't done it when it's WOT since I thought it didn't even wanna waste my time since it was reading 0.03v. Ill have to pick up a timing light

Ill check it out tomorrow since its getting late and dark. Ill lyk

 

Yes i made this mistake once and it read the same value as you read i believe haha hopefully its the setting that was wrong on the meter.

 

i just tried to read it but I was still getting nothing… are these settings right for the meter?

 

Try DCV 20,

The Official Honda TPS wiring and calibration thread - Honda-Tech - Honda Forum Discussion

 

my del sol b16a3 is having this issue, but a new tps didn’t fix it. i actually used a multimeter to measure the voltage and chose .45 as the closed throttle position. for whatever reason though, the WOT is only 4.1. any possibly clue anybody?
i also cleaned the IACV but no luck with that either. the revs are only bouncing around 1.5k.

 

Closed TPS voltage should be between .490 and .500v... and WOT (100% throttle) should then read above 4.20v, but not more than 4.70v. Now, since you have a B16A3 engine, your throttle body still has a FITV (fast idle thermo valve) bolted to the bottom of the throttle body. To test if this is your high idle issue, remove the intake tube exposing the front of the throttle body. With the engine idling, just inside the front of the throttle body opening you will find two small openings: one at the 8 O'clock position and the other at the 10 O'clock position. The latter is the port for your IACV. The former is the port that feeds the FITV. Cover the lower hole with your finger completely... if the engine immediately idles down to the normal idle speed, then your issue is the FITV. Google repairing the FITV... there is at least one or two good threads here on how to put one back together.

 

thank you for the help! i’m at work sadly, but when i get back home, i’ll do just that. i’ll also adjust the tps accordingly. i’ll update

 

i got the voltage readings fairly accurate now on the TPS .500 - 4.21. i plugged that hole at the 8 O’Clock position while idling, but idle didn’t change. i don’t necessarily have a problem with idle until the car is warming up, then it idles a bit higher. my main issue is the acceleration being aggressive, and somehow at slight throttle, the revs bounce at 1.5k. makes the whole car jerk around and makes it hard to take off smoothly at all

 

Try plugging the upper hole while the car idles at operating temperature and see if there is a drop in engine speed... it should drop the idle to almost stall (450-500 RPM) if the IACV works properly. If no idle speed change occurs, the IACV is not functioning. This could be caused by: 1) Wrong plug connected to the IACV (wire colors will be yellow/black and blue/black); 2) Bad IACV; or 3) No hole in the throttle body gasket to allow air through the intake manifold to reach the IACV itself.

A "Jerky" start from stop and the jerking continues until about 2200 to 2500 RPM... the IACV is likely your issue.

 

i ended up re cleaning the IACV and i no longer have that bounce at 1.5k revs. it does bounce a little when it’s warmed up but only every now and then, and that’s just at idle. it doesn’t jerk anymore either, and the throttle isn’t jumpy like before. i did try plugging up the IACV hole in the throttle body, and it totally killed my car haha