Another Newbie post... great

[dmchan]

So I'm not a complete newbie when it comes to wrenching on cars. I've gotten plenty dirty with head gaskets, timing belts and the like. I *am* a complete newbie to these 7M motors though.

I just purchased am 88 7MGE. The odo stopped at 195k. It runs and the price was right so I couldn't pass it up. Hopefully I wont have to sink too much into it to get it road ready. Now, before I ask for some assistance I will say that I've spent two days reading these and other forums on the issues I know it has. I've been through the TSRM sections that apply and I've been under the hood with my multimeter.

So - here's the deal, easy stuff first.

1- Power Steering is empty and has been driven as such for some time. The pump makes no noise that I have found. It's dead... right? Not like I can fix the leak, drop some ATF in and we're good to go?

2- Brakes are funky. Occasionally they are firm and work good for a few seconds, then they sink to the floor. The previous owner said he bled them, I asked how and he didn't know what the hell he was doing so there is probably air in the lines. But... I hear a strange squeaking like noise when the sink from time to time. Not like a hissing booster, though. Master Cylinder? (I haven't yet bled them myself, that's the first stop once I get this other thing done.)

Now - It seems to run rich based on the fuel in exhaust smell and the nice dark tint forming on the rear bumper. I'm thinking that is probably partly to blame on the fact that it likes to idle at around 2k. Start up it fumbles around 1k then slowly rises and levels off about 2k where it sits steady and smooth. Step on the throttle and she coughs a bit, then rev's nicely until you step on it again when it coughs again.

I'm getting code 51 so off I go with my tools. I cleaned the TB plate through the intake side with a tooth brush and starting fluid. Backed off the stop screw to make sure she's fully closed. No change.
Pop off the terminal and jump E2 and IDL (post I read says bottom two pins, TSRM shows top two. I went with the TSRM), code 51 disappears, 41 shows up. Good, wiring is in order. Now is where I hit the confusing part. I bust out the multimeter and start trying to get readings off the TPS but no matter what I do, swap pins, throttle in different positions, new multimeter ... no resistance reading at all. Is that indicative of a failing ECU or?

Any help you guys can give is most appreciated. I'm sure you'll be seeing more of me before this is over so feel free to thwack me on the head when I do or say something stupid. It'll probably happen soon if it hasn't already.

 

[dmchan]

... no resistance reading at all. Is that indicative of a failing ECU or?

So I was thinking on it and realized that I have, in fact, already shown my moron card....

Seriously, though - anyone care to throw me a line on this one?

 

[hvyman]

sounds like a bad tps.

If there is not fluid in the ps it prolly leaked out. Fill it up and check for leaks.

 

[Mr Bojangles]

These PS pumps are ridiculously tough. I had a major leak when I got my 88 beater and had no money to do anything with it. I ran it with no fluid lots of times because I didn't want it to just leak out all over. About 4 months later I fixed the leak and filled it up and it's worked fine ever since. Fill it up and test it out.

Bleed the brakes properly before wasting any time or effort on any other brake related goose chases.

 

[D.J.T.]

Wouldn't hurt to put atf in the power steering resevoir. It'll probably leak somewhere & the REAL ps problem will show up.

as for the brakes, bleed as usual. if that doesn't help. replace the brake master cylinder with an used one or one from the stealership. Reman from autozone, napa, oreilly's DO NOT WORK.
you can bench bleed them & see it work normal. But once on the brake booster, the rear pressure is dead. Idk if anyone else had trouble with Reman brake master cylinders...

 

[dmchan]

Thanks for the input folks. very much appreciated. I'll grab a new TPS from vatozone after xmas since I get no readings off this one.

Bled the brakes, no change. I'm about 95% sure its the master cylinder. I think I saw a link in my forum searching for an Aisin around here somewhere.

I know there is a pretty good PS leak as I can see the ugly crap from where it has leaked out all over the place. I'll have to study the TSRM a little more to figure out which line I need to buy.

Again, thanks!

 

[AbsoluteSpeed]

For the brake master, check under the dash and see if it has puked fluid down the inside of the fire wall.
Replacing the master won’t take long, I remember 1 bolt being hard to get to.

 

[D.J.T.]

For the brake master, check under the dash and see if it has puked fluid down the inside of the fire wall.
Replacing the master won’t take long, I remember 1 bolt being hard to get to.

Heh? i never remember the brake master being difficult to take off & install.. just loosen the brake lines & remove 4 bolts from where it mounts on the booster & voila.
& I never knew it could leak inside the firewall since its mounted on the booster away from the firewall? That'd be a bitch since brake fluid peels paint off

 

[dmchan]

TPS is giving me hell. Code 51 is gone but code 41 refuses to go away no matter how I adjust this sensor. Is it truly that sensitive? I haven't been able to get my hands on metric feeler gauges but I've used my c-mic to get pretty close to .7mm and used my digital multimeter - I just cannot seem to make 41 go away and the idle is still erratic and high. Any advice on this one? Also - if this code is present, can that truly be the reason for my high idle?

Ohm tested the IAC and it tests good.

Timing was advanced to 15 deg BTDC, pulled it back to 10. Idle still pretty damn high. (sometimes 1.5 up to 2.5k but usually right about 2k)

 

[hvyman]

Dont use the feeler gauge. Set the set screw to touching it so when you push on the throttle it opens smoothly.

Then set the tps. You hook the mm up to the 2 pins that it says in the tsrm and turn it very slowly till the multimeter deflects and then tighten the screw. Its more a reading to no reading or the oppisite. Can remember been a while.

 

[hvyman]

Dont use the feeler gauge. Set the set screw to touching it so when you push on the throttle it opens smoothly.

Then set the tps. You hook the mm up to the 2 pins that it says in the tsrm and turn it very slowly till the multimeter deflects and then tighten the screw. Its more a reading to no reading or the oppisite. Can remember been a while.

 

[dmchan]

Hmm - perhaps we're not talking about the same screw. There are three that I can see.

One rests on a diaphragm with some kind of filter attached. This screw is closest to the hood.

The second one is lower, closer to the driver side and set back toward the rear a bit on another part of the throttle linkage. This one, when screwed in too far makes it difficult to manually increase the throttle because of a little roller type bushing within a groove in the throttle linkage plate where screw #1 lives.

The third one is what I believe to be the throttle set screw and lives underneath all of the throttle linkage guts. It's pretty tough to access and I have not adjusted it at all. From reading these and other forums it is not to be touched as the factory has it set where it needs to be.


So- are you referring to screw #2?

 

[jetjock]

In order:

1) Set the throttle stop screw so the throttle plate is fully closed.

2) Set the TPS by continuity or measuring voltage between IDL and ground.

3) Set the dashpot per the book.


Code 41 is caused by only three conditions:

1) VTA less than 100 mv (shorted)

2) VTA more than 4.8 vdc (open)

3) VTA more than 1.5 vdc with IDL closed (0 vdc).


The idle speed control system will not operate unless IDL is closed.

The engine can not be timed unless IDL is closed.

 

[dmchan]

I think I am confusing myself now having it rolling through my brain for a solid day straight. It shouldn't be this complicated, I know.

Throttle is closed - I've stared down the pipe, pulled the TB loose to check and code 51 is not present.

I've adjusted the TPS by resistance and by continuity. (Mounted loose, turned completely counter clockwise, snugged screws and very, very slowly tapped the TPS in a clockwise direction until I lose continuity then tightened. Note that the multimeter will give a short chirp when the leads touch the IDL/E2 pins in this position but it is only for a fraction of a second and then there is no continuity tone given. ) I do not know how to adjust by voltage - would I need to go to the ecu harness for this?

I haven't found info on setting the dashpot in the TSRM. I guess I'm not looking in the right place.

Should code 41 show up with the harness disconnected from the TPS? Before hand I had code 51 showing up as well with it connected or disconnected, now it's gone no matter what granted that I dont press the accelerator or the A/C button. Is code 41 stored or real time?

At this point I am just making super fine adjustments to the TPS and sliding the harness back on hoping the damn code will stop flashing at me.

 

[dmchan]

Ok, scratch the code 41. I think I was following the GTE steps for the TPS. I started from full clockwise and turned counter until I got the change, bolted it down and now I get the constant fast flashing CEL. No codes. Yay.

Why the hell is my idle still so high, though? It's still running quite rich and idling just under 2k RPM. I'm confused - which is a pleasant change from frustrated.

 

[AJ'S 88NA]

Ok, scratch the code 41. I think I was following the GTE steps for the TPS. I started from full clockwise and turned counter until I got the change, bolted it down and now I get the constant fast flashing CEL. No codes. Yay.

Why the hell is my idle still so high, though? It's still running quite rich and idling just under 2k RPM. I'm confused - which is a pleasant change from frustrated.

Have you checked the timing again with a light and jumper wire?

Check for vacume leak also.

 

[dmchan]

@AJ - yes, I reset the timing. 10 Deg BTDC.
I've suspected a vacuum leak from the beginning but I've sprayed starting fluid all over the place and cannot seem to find one. With no codes that means the TPS is set correctly now, right?

 

[jetjock]

I r corn-fused. What makes you think a vacuum leak will cause high idle and how/why did you set the timing with it?

 

[dmchan]

I r corn-fused. What makes you think a vacuum leak will cause high idle and how/why did you set the timing with it?

I've seen un-metered air entering the system cause high idle conditions with other motors in the past. I popped the brake booster vac line on this one and it does bring the rpm up with a significant leak. I do not hear any audible leaks, though. It's a pretty quiet motor. Very little valve noise.
As for the timing, I was hoping the jackasses that had their hands on it prior to me had it timed wrong causing a very high idle. Neither of these seem to be the case. I'm assuming that even with the high idle, when you jump the te1 and e1 pins you can set the timing. Is that not the case?

I'm wondering now if I can have a bad sensor without any codes present. I hate shotgunning parts into a vehicle when there has got to be a way to track down the problem without wasting money. The other symptom that seems to fit in but I can't figure out is the hiccup when you mash the throttle pretty good. It coughs slightly just a second then revs cleanly.

Damn I wish I had a supra experienced friend down here in S. Texas.

 

[jetjock]

Ah well, I tried. Good luck with it...