95 Saturn SC2 5sp 144k with slightly high idle

[fritcr]

Some of you have read my tale of my first engine swap. It is all done and in. It now runs smooth and has plenty of power. I have a few small problems...
It "seems" to idle a little high. It it usually just under or right at 1000 rpm on the tach. Sometimes seems to take bit to come down to idle when pushing the clutch also. Just a reminder...the donar engine came out of an automatic car. I was told by a someone that the only difference was the flywheel and that all of the sensors, computer etc were the same. I cleaned the TB good before I put the engine in. I didn't take the IAC off..in fact..I'm not sure where it is. I really have not looked for it. I might try to clean that tomorrow.
Second problem is, and probably related, the service engine soon light comes on sometimes but usually not. I drove it for 1/2 hour and came to a stop light and pushed the clutch in and it idled fine for about 1 min I guess then it idled up to about 1600 rpms for a few seconds then back down and the light came on. It stayed on until I restarted the car later but never came back on that day. It has came on once before when sitting and idling in the driveway early on when I was filling antifreeze etc. I do have the old engine and all sensors etc in the shed. BTW...the ETCS on this engine was brass and looked good but I can buy a new one if you all think it could still be that. I put a new thermostate in it before putting the engine back in. Any ideas for me to try. My dad has a scan tool but only for the newer cars and it won't read this one so I can't get the code.
Rob

[Cat Fuzz]

A paper clip is the only scan tool you need to get codes.

http://www.differentracing.com/tech_...diag_info.html

[RC1488]

Clean the IAC.

Also during a high idle, turn the car off then on again. If the idle returns to normal, its the TPS (throttle position sensor)

[saturnspeed_12]

to begin, cars with auto have a different pcm then a manual. yes they can plug in, but they are different. you can use a auto pcm in a manual, and you will throw some lights constantly, but other then that you will lose your rev limiter and ive noticed the idle is slightly higher.

now with the high idle, that sounds like a tps problem. there have been some problems with loose connections. if it starts to idle high, play with the tps connector to see if it goes back down. now the iac on the saturns acts strange, and can react slow. the iac (idle air control) is located on the right of the throttle body at the bottom.

also the car will normally idle between 750-900 rpms. your tach is probably off slightly. the only other problem could be you have a vacuum leak

[fritcr]

Sorry for the long times between posts but I have to travel some for my job. Anyway, back at working on the Saturn. I put the upper Motor Mount from the other engine on it and then adjusted the dogbone. That seems to have fixed the unusual vibrations. I took the throttleplate off the intake and took all of the sensors off. Cleaned it all really good and put it all back together with the IAC and TPS from the old engine. (thanks to the video from RC!!!)
I still have a high idle. At least I think so. It usually idles at about 1000 or 1100rpms. It does idle smooth and runs great. If I let it sit for a minute or so at idle then it will idle itself up to about 1500rpms for a few seconds then it falls back to 1100 and the service engine light comes on. It did this before and the code was TPS but this is a different TPS that seemed fine on the other engine. Any other ideas for me to look at? Oh yeah RC..turning the car off and back on does not change the idle but it does make the SES light go back out until it does it idle thing again.
I think most everything else is good now.
Rob

[RC1488]

Originally Posted by saturnspeed_12

to begin, cars with auto have a different pcm then a manual. yes they can plug in, but they are different. you can use a auto pcm in a manual, and you will throw some lights constantly, but other then that you will lose your rev limiter and ive noticed the idle is slightly higher.

Irrelevant to the OP's issue. He changed the engine NOT the PCM

OP: Tap the TPS with the end of a screw driver during the high idle. If the idle changes then its the TPS.

Check the connections to the TPS and IAC.

Check the Connector to the ECTS. A brass ECTS is no good if the connector is corroded.

Since youve just done and engine swap, make sure the throttle cable is routet correctly. It should be going up between the 2nd and 3rd intake runner parallel with the injector harness.

Did you damage the throttle body gasket?

During the engine swap did you use the remove the intake manifold from the engine in the car now at any point? If so, did you replace the gasket when putting the manifold back on?

Post the SES code specifically please

[fritcr]

Ok another update. I put a new brass ECTS on just now. The connections on all sensors look great..just doublechecked them. I cleared the 49 code which is high idle out of range. Started it backup and the ses light came on again and now it is code 35 which is idle control high idle. It's one after another with this car! haha
I did check the throttle cable and it is correct. I did not take the whole intake off of this engine but did take the plate part off (where the sensors are) and NO I didn't put a new gasket on it. BUT I did just spray electronic cleaner around it with it running and got no response from any connections. Vac or other for that matter. Still idles just over 1000rpms.
I'll try to tap the tps when it idles high again.
Rob

[RC1488]

Originally Posted by fritcr

Ok another update. I put a new brass ECTS on just now.

The one with the two wire connector correct?

[fritcr]

Yes the one with the 2 wires. I put the new one in and it acts the same with the code 35 now.

Idle Air Control (IAC) - RPM Out Of Range
The idle air control (IAC) consists of a two coil stepper motor controlling a valve. The motor is
used to move the IAC valve pintle in and out of a seat to control the amount of air that enters
the intake manifold at idle.


Diagnostic Trouble Code parameters:
DTC 35 will set if:

Idle speed is greater than desired after PCM commanding the IAC motor closed.
Idle speed is greater than desired after PCM commanding the IAC motor wide
opened.

So now I don't know if I have a bad iac or what. I took the one off the orginial engine and it did not have this problem. Unless I did something wrong when installing it. I just basicly put it back in there. Did I need to do something to set it?? I will still try to tap the tps but I'm not sure it would prove anything since it only idles high for a few seconds. I would automaticly go back down before I could really "tell" if made a difference. As long as it don't idle to long warm it will not do this or set a code. I drove it for over and hour this morning before I got the high idle (1500rpm) and code at the first stop light I got to.
Rob

PS...thanks sooo much for helping me with all of this and sticking with a rookie!
Rob

[RC1488]

Try this:
Remove the IAC again. Pull it out a little (i forget if it pulls or twists out). Then replace it. Remove the PCM B fuse in the underhood junciton box for 1 min. Then replace it and start the car. It may surge right away but let it sit for a little and see if it idles normally. Drive her around and see how she goes

[fritcr]

Ok I will try that. It is bitterly cold here tonight and I'm not feeling well but will try that tomorrow after work if I can. Would you get a TB gasket if you were me? It seems to have sealed back up ok but it is almost easier to take it back off to get to the IAC.
Rob

[RC1488]

As long as its on correctly (as in the two holes in the gasket line up with the two bolt holes. I missed a bolt hole and had a big idle surge from the leak ) Then i would not get a new one.

Feel better though!

[fritcr]

It finally warmed up a bit here and I was able to work on the Saturn some. I took the TB off again and put the spare IAC on it. It does the same exact thing. Except now the code is back to the 49 code. something about idle to high or whatever.

RPM - High Idle (Vacuum Leak)
The vacuum lines include the MAP sensor junction, PCV hoses, PCV valve, brake booster hose,
the fuel pressure regulator hose, throttle body, intake manifold gasket and throttle body minimum
idle adjustment. DTC 49 detects a leak in any of these lines which may cause the idle speed to
rise above the control of the IAC system. DTC 49 is detected when engine idle cannot be reduced
by the IAC motor and the IAC is determined to be working.


Diagnostic Trouble Code parameters:
DTC 49 will set if:

The engine is idling higher than desired rpm.
The IAC is working properly.

The gasket looks fine and stays stuck on the intake. I actually ment to pick one up for it in town while ago and totally forgot. I can go get one tomorrow I guess. It never came off the intake so I know it is on correctly.
Anyway, I'm stumped. I don't know what to do with it. It also idles up around 2k when your driving and push the clutch in....takes a bit for it to come back down to 1100 or 1200rpms where it stays.
If left to idle for a few minutes after it warms all the way up then I get the idle up to 1500rpm and right back down to 1100 and then the SES light comes on. It is very strange.
Anymore ideas?
Rob

Thanks so much for sticking with me on this and helping me out.

[RC1488]

Post your results for each:

-During the high idle, shut the car off then back on right away. See if the high idle goes away.

- Spray along the intake manifold gasket with brake cleaner around each cylinder. See if the idle changes.

-Tap the TPS with a screw driver end...see if the idle changes.

-Make sure hoses going to the top of the TB are connected at both ends. Sometimes during an engine swap they are forgotten to be connected under the intake manifold.

[fritcr]

Since my last post I have gotten a TB gasket and while I had the TB off AGAIN...I checked the range or whatever of the TPS while I had it off. It did not jump around at all. Starts high on the ohms and slowly goes down as you open up the throttle. Put it all back together with the new gasket and cranked it up. Let it warm up a bit and took it for a drive. Still high idle...in fact it seems worse now. Anyway, got the ses light when I got back and let it idle so I got some carb cleaner and sprayed the crap out of everything I could think off with no change at all in engine rpms. I sprayed the intake and all vac hoses etc. Around TB, egr, and map sensor. I also put the extra Map sensor on just in case. Checked the vac lines from the top of the TB that go to the FPR and then down to the side of the engine. NOTE: I did snap off the plastic line going down to that thing on the side of the engine when we put the engine in. I put a piece of tight vac hose over the 2 ends. Also found a hole in the vac line going from that piece to the firewall at the time of engine swap and replaced that too. I took the hard vac lines off the old engine yesterday but didn't have time to put them on this one. I might try to do that today. I don't think that could be the problem but don't know for sure.

Ok, shuting the car off and on when it idles up does makes it idle even higher then it settles down but really...that would not tell us anything because it only idles up for a few seconds and by the time I turn it off...it would have been back on it's way down to 1100. It never ever idles below 1100 rpms.
I have not tapped the TPS but will do that today...I meant to do that yesterday but forgot. I'm about ready to give up and take it somewhere but I don't even know where to take it. We don't have a Saturn dealer anywhere near here. I guess I can take it to a local shop but I don't know what they would do that I have not.
Rob
Thanks for all of your help Rich.