Funky starting issue

[Warlock1]

So when I bought this car it supposedly had a lot of "stuff" done to it. Rebuilt engine by a "mechanic" ported head, rings, bearings, metal head gasket, yada yada yada. Also a Walbro fuel pump was put in. The FP relay is bad so there is a jumper in the diag connector for the FP.
So the kid told me that sometimes it wont start and what they do is pull the #1 plug wire and crank it and it'll start. Yeah right I thought, whatever.

So after working on the interior all weekend I try and start it and lo and behold it doesn't. Sounds like it wants to catch the first try if you leave it sit for a while, but the next few attempts results in it just turning over. I attempted this on and off for a few days with the same result.

So I attempt to start diagnosing and pull the #1 plug wire and check for spark and the damn thing starts. I kill it and reattach the plug wire and drive it around the block. It ran good but it almost has a rich smell to it. Tomorrow I am going to check base timing and readjust the TPS. Oh and it also idles high like 1100 rpms and the book says 650 for a gte and I did check codes and it has a 51.

I have to admit this one has me a little stumped. I'm sure it has something to do with what those wrench handlers did, hell I'm still finding loose bolts that they never tightened.

 

[IBoughtASupra]

When you say unplug number one cylinder wire, do you mean off the plug itself or up off the coil pack?

You might have some bad CPS wires or a maybe of you have to unplug one number cylinder wire up top from the coil pack itself, maybe bad wires there.

Check the CPS wires. They are on the exhaust side of the head, in the front behind the thermostat housing.

 

[Warlock1]

off the plug itself. I mean its really strange. I literally never touched any other wire(s). I'm going to try and start it again tomorrow after work and see if she fires.

 

[Warlock1]

Ok so came home and installed a new FP relay and verified that it now works. So the car started without issue. I started to check things out and I removed the black connector to the TPS and checked the bottom connectors for continuity. Awesome it reads 0 fully closed, but wait a minute it also reads 0 throughout the whole stroke. WTF Can these engines even run without a working TPS. Mind you I have driven this thing around the block several times. It seems to have good pickup and idles good although a little high. Yesterday though it did smell really rich. Waiting for suggestions???

 

[supraguy@aol]

If your tps is adjusted far enough off, it could read zero throughout, i believe.
And yes, it can run with a bad tps.

 

[jetjock]

A few things to keep in mind:

1) Ignition timing can't be set unless IDL is low (tps contact closed).

2) The ISC system will not operate unless IDL is low.

3) If IDL remains low the engine will fuel cut at appx 1600 rpm.

 

[Warlock1]

JJ I was looking at another tread you had written, so I was going to do the tps first and then check timing. So I understand the first two but the third item bugs me as I was able to drive this thing around the block and down the street and I know I got it to well over the 1600 rpm range. Now if my meter readings were right and I'm sure they were then that doesn't make sense to me. I checked the bottom two tangs of the connector and the meter read 0 ohms and then when I swept the throttle the meter never changed.
I will pull the tps off tonight and check it on the bench.

 

[jetjock]

Didn't make sense to me either which is why I pointed it out. Perhaps you got the pins wrong. You wouldn't be the first.

A jumper across the proper mating terminals on the harness side should cause fuel cut:

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=125

Edit: Now that read the first post again I see you have a 51. That imples you did indeed have the wrong pins. Can't have a TPS related 51 with IDL low.

 

[Warlock1]

So using the page you sent me it looks like the top two pins are the ones I am supposed to be using, however on the link I posted it is showing the bottom two since this is a GTE.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101

I will try the fuel cut thing tonight. thanks for sticking with me here.

 

[jetjock]

That bit of confusion is common. Iirc the pins you want will be gold flashed. That said there isn't any combination of pins on a TPS that should measure zero ohms (or nearly so) at all times so something is goofy. Course, all this has zip to do with your starting problem.

 

[Warlock1]

So I checked the values of the TPS with the ones in the manual. I was able to adjust to get right in the middle of all the values at fully closed and fully open although the one where you use a feeler gauge I never really understood. Maybe because I can't read what the note says. So after that I adjusted the timing and was able to get it to settle right around 750-800. BUT as I was adjusting the CPS and moved the wires the engine stuttered. So I tapped on the connection and it did it again. Then I started to move the wires and it eventually stalled. I was able to start it right back up, but I know now that I need to check the wires and the connector. The connector tab is broke so I may have to find another and solder it in. The car still seems really rich though (by smell) I'm wondering if I don't just need to run the piss out of it and blow out anything that might have accumulated in the cat. All I can say is getting closer.

 

[jetjock]

In diag mode the MIL will show code 51 when the gas pedal is slightly pressed and not when released. If it does the TPS is set close enough. Never time the engine without first doing this test or at least checking for codes.

Fix the CPS wiring. It's a common problem although I never had it. I suspect it happens because certain parts disappear over the years.

Verify the engine is in fuel control by checking the O2 sensor directly (OX terminal) or use Vf when in diag mode and off idle. See the TSRM for details.

 

[supraguy@aol]

Warlock- Driftmotion.com sells the replacement cps connector for dirt cheap.

 

[3p141592654]

EDIT: Deleted my post... Never mind, I wasn't paying attention to what you wrote.

 

[Warlock1]

In diag mode the MIL will show code 51 when the gas pedal is slightly pressed and not when released. If it does the TPS is set close enough. Never time the engine without first doing this test or at least checking for codes.

Fix the CPS wiring. It's a common problem although I never had it. I suspect it happens because certain parts disappear over the years.

Verify the engine is in fuel control by checking the O2 sensor directly (OX terminal) or use Vf when in diag mode and off idle. See the TSRM for details.

Roger that JJ, I'm out of town for the week so I will check this when I get back.

 

[Warlock1]

I verified that there wasn't a code 51 present. I switched the car on and then jumpered the diag pins. No 51 present. I then slightly pressed the gas pedal and it appeared. it disappeared when I released the pedal. I then f'ed up and tried to start it with the pins still in place and it wouldn't start. So I removed them and pulled the efi fuse to reset everything. Still no start. It acts like it wants to but it just doesn't fire. Also now it acts like its to far advanced. It will start to turn over and then turn over again.

 

[jetjock]

So the IDL contact is OK. Fix the CPS wiring. If the engine has spark, fuel, and correct timing it has to run...right?

You can start and drive the car all day long with the diag jumper in. Doesn't matter once you're off idle.

 

[Warlock1]

I'm with you JJ I think it has something to do with the CPS so I am going to concentrate on that today. I did find a used one for 100 bucks if it turns out to be bad. Is that a reasonable price?

 

[Warlock1]

OK so car just became a long term project. As I was checking the CPS, I was verifying the pick ups and two out of the three were over the allowable limit. So I thought to myself "self turn the engine over to make sure the values don't change". Well when I put a ratchet on the crank pulley bolt I found it wasn't even finger tight. As I tried to tighten it, I couldn't hold the pulley enough to get a good torque on it. So with the lack of confidence I have that the "mechanic" that built this did it right and the abundance of leaks it has, I am just going to pull the engine and go through it. Along with the interior pieces I just can't find this is really getting me down. I took a f'in on this one.

 

[Warlock1]

Ok so I received 2 CPSs today. 1 was supposed to be a known good and the other was unknown. I checked them both and all the pins read 230 or greater on the ohm scale. According to the TSRM they are supposed to be 140-180 ohms. So that means they are bad correct? I know its a simple question, but before I call fowl I want to be sure and yes I bought them from a member here. Hopefully they just didn't know and they will make it right if they are bad.