98 SL with 99 TPS?

[JScottB]

I just bought a 98 SL1 with a bad TPS but the correct TPS for a 98 won't work but a TPS for a 99 will even though everything on the car says it's a 98. I'm assuming 98 was a change over year meaning some 98 SL's may have had 99 components. This will be my kids car so you can bet he'll be messing with aftermarket performance parts but if the car has 99 components (at least the TPS is a 99), should he assume all computer contolled related components are 99 when ordering parts?

[RC1488]

The TPS is the same. My tps from my '02 will fit your '98. Along with my '95 tps.

[JScottB]

You sure about that? I can see possibly the 02 being the same but the 95? Where the wires connect to the TPS on what's currently in our 98 has an oval shaped connection while the replacement ACDelco TPS (throttle position sensor) has a round connection which according to every search I've done, that's what it's supped to have. Just for kicks I changed the model year to 97 while searching and again found the same round connection TPS and same part #. It's when I changed the model year to 99 when searching that I found the correct TPS with an oval shaped wiring harness connection identical to what's on my 98. I went back to the dealer and they too had a different part # for the 99 TPS and the visual they showed was identical to what is currently on my 98 meaning it too had the oval shaped connection.

[RC1488]

I stand corrected! I do apologize.

Went down stairs- '97 TB has a circle TPS connector. '99 TB has an oval connector.

Get which ever fits your car. They function the same regardless of the sensor. A '99 TPS will work fine.

As to your son modifying the car, go by the VIN. Or check back here as many have already done what he wants to do

[JScottB]

Thanx for the input anyhow RC1488, I do appreciate it.

I put the new TPS in and I still get a check engine light except instead of coming on as soon as the car starts like it did with the old TPS, this time it waits about 1 min to come on after the engine's running and it idles a bit high. I put a scanner on it to see what fault code it had but the scanner said all was well. I'm kind of new to dealing with all the electronics so I can't explain why I'm getting a check engine light but no fault code but being it idles high, I've got a hunch that I've got a vacuum leak somewhere. Another problem unrelated to the TPS is that the temp gauge in the dash hardy budges past the "cold" mark even when it's fully warmed up so it's probably got a bad temp sending unit as well. All in all the engine runs fine but it's the little details like the check engine light being on with no fault code and the temp gauge that drive me nuts. I'll fill you all in when I find something.

[RC1488]

Originally Posted by JScottB

...the temp gauge in the dash hardy budges past the "cold" mark even when it's fully warmed up

Replace your ECTS ASAP!! The stock sensor is resin and cracks sending false data to the PCM. New ones are brass. ECTS is used by the PCM for Idle rpms, temp readings on the dash, air/fuel mixtures, IAC posistion and much more. If yours is cracked the PCM probaly thinks the engine is cold and raises the idle so it will reach operating temps. Kind of like starting the car in the winter. Once you have the brass ECTS and it takes a while to warm up, the next thing is the thermostat. however untill you get a brass ECTS the guage on the dash cannot be trusted as an accurate measuring device.

Another diagnosis for the high idle is to check the intake manifold gasket. You have a SOHC and tho its more common on the third generation SOHC, it hasnt been unheard of leaking on earlier years also. Spray some carb cleaner aroung each cylinder at the gasket and see if the idle changes. If it does, you need a new gasket. Do this AFTER you change your ECTS.

As for the SES Code...go to autozone and have them help you. If your SES light is on there IS a code! You may have to have the scanner scan the entire car's systems before you can read it. Autozone/advanced auto can help

[JScottB]

You nailed it RC1488 ....except I was 1 step ahead. Prior to replacing the ECTS I took it over to a local mechanic who I feel has the best code scanner around here and he knows how to use it and he came up with codes 1650 and 1651. I already had a hunch about the ECTS and he agreed that was a good place to start. Once I replaced it, started it up and let it warm up, the temp gauge in the dash responded like it should and the engine's idle came down to around 600/700 rpm. The problem is that the check engine light still comes on. I haven't rechecked the trouble codes since I replaced the ECTS but I'm going to investigate codes 1650 and 1651 some more and fill you in on what I find. Thanx again for the input.

[RC1488]

Fantastic! Reset your codes now and see if they come back. The SES light will go out eventually if the ECTS was setting the codes off however it may take a few days. If you remove the PCM B fuse for about a min or so located in the fuse box under the hood, the PCM resets and the codes are cleared. If the light comes back, then pop that scanner on again and see what the codes are. Good luck!

DTC P1650 Control Module Output B Circuit
DTC P1651 Fan 1 Relay Control Circuit

[JScottB]

FOUND IT!! and it was a STINKING LIGHT BULB. I wasn't aware of it until I was thumbing through the owners manual today but I found out our Saturn has 2 service lights, the service engine soon light and the service light with a wrench and it dawned on me that I never seen the SES light at all. I assumed the service light with the wrench was the only one and that was the light I was seeing all the time. So we remove the gauge cluster and started checking bulbs but it was difficult to tell if the SES light was out so I used a volt ohm meter to check for continuity and sure enough the SES bulb was out. I replaced it plus another one that I thought was questionable. Got everything back together, turned the ignition on and all the lights came on like they should when you first turn the key but both service lights went off and stayed off once the engine started.

[RC1488]

Awesome!

haha yes there is an SES light and a Wrench light.

Glad you car is back in action!