bad TPS?? 5S-FE

[97vulcan]

Hello,

I've looked at replacing my TPS due to a surging idle on occasion, and sometimes a no start. Does this sound like problems caused by a faulty TPS?

Also, is it a straigt replacement? I mean, is it as easy is swapping out the old one with the new one??

and is O'reillys auto parts TPS any good?

Thanks,
Adam

[hill8570]

I think you're barking up the wrong tree.

About the only way I could see the TPS effecting idle is if the idle switch isn't registering, and in most cases I would assume a code would be set for that failure. Even then, can't see how a TPS could cause a surging idle.

Did you test the TPS to see if the idle switch was working?

BTW, as a general rule, parts from any chain parts store other than NAPA are Chinese crap (NAPA sells mostly to "real" mechanics, who tend to get downright irritable if they have to spend free labor changing out a crap part they just installed). If you have to shotgun parts, use a junkyard pull.

[97vulcan]

I didn't check the TPS to see if it's working properly as I'm not sure how to.

is it possible I have a trouble code, even if the CES light is not illuminated?

I guess whats throwing me off, is I know the ignitor is good, and when the car is running in neutral, park, or driving it's fine. No loss of power that I can detect with the butt dyno.

sometimes it starts, sometimes it doesn't, and that's the most confusing to me. Also, sometimes it surges at idle when in gear all the time, and sometimes not. Seems to me something is working when it wants to.

Thanks again for your help!

[hill8570]

Originally Posted by 97vulcan

I didn't check the TPS to see if it's working properly as I'm not sure how to.

is it possible I have a trouble code, even if the CES light is not illuminated?

I guess whats throwing me off, is I know the ignitor is good, and when the car is running in neutral, park, or driving it's fine. No loss of power that I can detect with the butt dyno.

sometimes it starts, sometimes it doesn't, and that's the most confusing to me. Also, sometimes it surges at idle when in gear all the time, and sometimes not. Seems to me something is working when it wants to.

Thanks again for your help!

See www.camrystuff.com , Generation 3, 5S-FE section, page 376 for the test specs for the TPS...any cheap-o multimeter will do for the testing. The Gen3 rigs don't do a lot of diagnostic testing on the TPS, so it's certainly possible to have a bad TPS without a code. Frankly, the only part of the TPS that could have any influence on the idle performance would be the IDL switch itself, but, even the, I don't think it would cause a surging idle. If you suspect an intermittent open on IDL, one thing to try would be to pull the TPS connector, and see if the surging starts to occur (this simulates an idle condition where IDL is open). Then short the two bottom terminals of the engine side of the connector (IDL and ground), simulating the IDL switch being closed, and see if the surging goes away.

[97vulcan]

thanks for your help! I unplugged the TPS last night when car was idling in park. The only thing it did was start idling over 1000 RPM. at that RPM the idling surge is not an issue.

Are you thinking at ECT sensor could be the problem?? that could be the issue, but would it cause a surge at idle in gear, and a no start sometimes?

Thanks again!!

[hill8570]

Originally Posted by 97vulcan

thanks for your help! I unplugged the TPS last night when car was idling in park. The only thing it did was start idling over 1000 RPM. at that RPM the idling surge is not an issue.

Are you thinking at ECT sensor could be the problem?? that could be the issue, but would it cause a surge at idle in gear, and a no start sometimes?

Thanks again!!

Well, the ECT is a long shot -- it can cause a no-start condition (by making the ECU either go far lean or far rich, depending on the failure), but I've never heard of a failed ECT causing a surging idle. While it's always possible we're looking at multiple failed components, I like to ass-u-me that it's only a single failure.

Offhand, my money would be on an intermittent, large vacuum leak. A big leak will definitely cause a surging idle, and on the 5S-FE with the MAP sensor, generally won't cause a problem at other than idle. It'd take a big-ass leak to lean things out enough to cause a no-start, 'tho -- you'd think you'd be able to hear the sucking sound from across the room.

[97vulcan]

Originally Posted by hill8570

Well, the ECT is a long shot -- it can cause a no-start condition (by making the ECU either go far lean or far rich, depending on the failure), but I've never heard of a failed ECT causing a surging idle. While it's always possible we're looking at multiple failed components, I like to ass-u-me that it's only a single failure.

Offhand, my money would be on an intermittent, large vacuum leak. A big leak will definitely cause a surging idle, and on the 5S-FE with the MAP sensor, generally won't cause a problem at other than idle. It'd take a big-ass leak to lean things out enough to cause a no-start, 'tho -- you'd think you'd be able to hear the sucking sound from across the room.

I don't think its a vacuum leak, as I can't hear a hissing or sucking sound. I actually think it's running more rich than lean. Just not sure where/what to try and diagnose next.

appreciate your help!

[97vulcan]

Hello all,

it appears it was a bad ignition coil. I ended up taking it into the shop because I couldn't figure it out. It seems to be fixed. I took the old coil with me, because I wanted to test it out. Is there a way I can do this??

Thanks again for all your help

Adam

[hill8570]

Originally Posted by 97vulcan

Hello all,

it appears it was a bad ignition coil. I ended up taking it into the shop because I couldn't figure it out. It seems to be fixed. I took the old coil with me, because I wanted to test it out. Is there a way I can do this??

Thanks again for all your help

Adam

You can ohm out the coils easy enough -- primary is the two small screw connectors on the coil. The HV side of the secondary is the big lug -- you test the secondary resistance between the big lug and the left-hand side of the primary (assuming the big lug is facing toward you). You can test for a heat-related issue by hitting it with a heat gun or a hair dryer and then measuring the resistance. Test for mechanical problem by very lightly tapping with a hammer while measuring resistance. Testing for real sparking is harder -- you have to rig up a spark tester (most parts stores have them), connect the left-hand side (the common between the primary and secondary) to 12V, and ground / unground the other side of the primary while watching spark.

I've got my dizzy pulled out of my rig at the moment -- I'll try to remember to take a picture of the coil to make it easier to understand.

[hill8570]

OK, here's a shot of the coil..this one is still in the dizzy, but the one you've got should be the same except there won't be nuts on the top two terminals.

The primary is measured by measuring the resistance between (1) and (2). It's a real low resistance, so be sure to short your ohmeter probes together before measuring so you can subtract off the resistance of the probes.

The secondary is measured by measuring the resistance between (1) and (3).

To check spark, attach a spark checker to (3), and ground the other side of the checker. Attach +12V to (1), and then ground / unground (2). Every time you unground (2), you should get a spark.

[97vulcan]

thanks for your help!! How hard is it to replace the coil? I took it to the shop because I couldn't figure out what was wrong. Should I have tried to replace it myself?? I got handed a hefty bill.

Thanks,
Adam