Had to install new harmonic balancer and now it only runs if the timing is about 40 degrees advanced. I tried to lower the timing and it wants to die and miss badly. I have a 85 FSM and it says to short T & E1 so that's what I did. Seems to run best at 40 degrees advanced. What am I doing wrong?

 

Make sure that the idle speed is not more than about 850RPM and that the TPS is sending the correct 'throttle closed' signal to the ECM.

Around 40' advanced is what you see when the ECM is setting the timing at low RPMs' without correct RPM and throttle position info.

In such a situation, the timing jumper will not do its job.

 

ok, so how do I get it to idle at 850. It wants to die from missing bad. The engine is fresh but it has been having missing issues since I adjusted the air gap on the distributor to 0.016. what is shorting the T & E1 actually doing? Do you know how to set the throttle plate gap on this year. The book I have is not correct on that subject. I messed with the stop screw and I wonder if that is having an effect on the TPS. Not sure where to start.

 

Why would you set it to the maximum? It should be as close as the radial play in the dist allows. Aim for 0.012" / 0.3mm and it will have a better signal.

The stop screw is there to take the play out of the mechanisim, Make sure the plate is fully closed, run the stop in until it touches, give it another 1/4 turn and lock it down. Verify the vacuum ports still appear as the diagram, on the filter side of the plate, after you lock the locknut.

Then you can test and adjust the TPS.

If your timing is still way off we'll pick after you fix this stuff. =P

 

Thanks for the help. Will make those changes tomorrow.

 

ok, changed the distributor air gap to 0.012", timed it at 5 degrees at around 750 rpm, it was bearly running at that speed, it wants to run at 1300rpm with an advance of around 40 degrees. I also backed off the throttle stop screw till the plate was closed and then turned it 1/4 turn clockwise. I also removed the upper intake manifold and ohmed each injector. All checked at 2.1 ohms. I did find a 2-wire connector near the back of the engine not plugged into anything. Maybe it has to do with the missing? I don't know what to do at this point.

 

Going back to the original post. Lets talk about the new harmonic balancer some.

Is it really new, and where did you source it??

Did you verify that the mark on it showed 0' on the oil pump scale with the crank key @ 12:00?

On a different note, does your truck have its EGR connected? Have you verified that the EGR is closing tight @ idle? Just a thought.

I don't know about your plug.

 

Yes the balancer is brand new. got it from carparts.com for $55. I did verify that the key and the index mark lined up. How do I verify that EGR is closed at idle?

By the way, the ignitor, coil, MAF, exhaust manifold, harmonic balancer and water temp sensor are all new. no miles yet.

 

I guess the only real way to tell about the EGR would be to block it off and see if your condition changes.

Even a little EGR seepage can ruin idle.

As a more gross EGR test, you can use a Mity-vac or other vacuum pump and pull vacuum on the EGR valve servo.

If the EGR passages are clear and the servo diafram is sound, this should stall the engine when running at idle.

This test won't show small seepage when the valve is supposed to be closed though.

When you have changed so many parts at one time, it can be difficult to determine where the real problem lies.

It is oftern best to change one part at a time to see what happens when that one variable has been changed.

 

Looks like a vac switch wire not sure which one it would be on the 88 Cali version. Same shape as the AC in my 86 fwiw.

The sensor there in the photo is the EGR temp sensor and might indicate a leak if you monitor it.

 

it was running better with a slight miss a week ago before I tried to time it and noticed the bad balancer. I may have to remove the EGR and clean it. I just tried idling it with the TPS disconnected. It ran better but still was advanced and didn't rev as good as with connected. One other thing. the O2 sensor has given up as of yesterday. I have a new one to install but was thinking of waiting till this problem is solved. would the O2 sensor cause missing? maybe the plug in the picture is for optional AC which I don't have. The EGR is the best idea so far. that would cause random missing. Thanks

 

Ok, I am making progress. I installed the new O2 sensor and blocked the EGR passage. When I started it up it ran a little better and was still showing the 40 degrees advanced. Then I shorted the T & E1 and it idled down around 750 and was timed at 6 degrees. It seemed to still have a minor miss but went back to 1300 rpm when I pulled the short wire. What is going on?

 

Now it's throwing a #4 code (water temp sensor). I replaced the one on the right, so I guess the one on the left is due. Cleaning the EGR tomorrow morning since blocking it made it run smoother. Still wondering why the idle shoots up to 1300 when the test wire is removed.

 

I think it's because the spark timing advances when the jumper is removed.. I still think that there's a TPS issue as well.

 

I'll look at the TPS after I clean the EGR. Thank you.

 

Pinch the AV hose closed while it's warmed up. RPM shouldn't change much if any. But I bet it drops to normal. Which is related to the temp sensor failure, it doesn't even have to fail just be off a few degrees.

 

AV? is that air valve? I'm new to this truck so I don't know all the parts yet. Is that under the manifold?

 

Which book(s) do you have by the way?

Yes AV, air valve. 10mm ID hose running vertically down from the front side of the throttle to the "box" mounted under the intake. It's a thermo valve that bypasses the throttle plate to increase idle. It is regulated by the ECU based on the reading it gets from a sensor, the sensor you got a code for.. and the actual coolant temperature of the coolant running through the two small lines.

 

Good idea. I had the opposite problem: no fast idle ever and would die at idle on really cold days as a result. Now on chilly days I get about 1100rpm fast idle at warm-up which drops to 750rpm. The idle air control valve is adjustable by a little Philips screw that would be hard to see installed. It adjusts a little plate which slides over the air passage to close it once it's coil receives warm coolant. The IACV It's only mounted by two 10mm screws to front of the lower intake (and the 2 large air hoses, 2 small coolant hoses). Once removed can be tested in your freezer for correct adjustment. Also test it's coil for resistance.

 

I had already replaced the coolant temp sensor last month due to it being wobbly. I don't know why the code came back again. I cleared it out to see if it comes back again.

Today I removed the EGR and soaked the valve in carb cleaner for an hour. While soaking it, I noticed fluid would run easily through the valve and the diaphragm was still working good. After installing, it ran about the same at idle but with a slight touch of the throttle, it torqued over and ran strong and smooth. The problem is, it only needed a millimeter of throttle movement to make that happen. So, thinking I had the right section in my Toyota 85 FSM, I adjusted the TPS without feeler gauge to read 0.5k ohms between E2 & VTA terminals. This made it worse. After reading a little further it says to use 0.018" feeler gauge between the stop screw and the lever, measuring between E2 & IDL, and turn the TPS clockwise until it deflects the meter. I'm assuming this means it goes to infinity? Or is continuous? Bad FSM.. I got this copy online. I will go redo the TPS adjustment as soon as I get up the motivation again. So confusing.... Any other ideas?