xalier

like it says im trying to set the timing on my 90 pu with a 22re and when i put the jumper wire on te1 and e1 the idle doesn't change... what could cause this? how am i suppost to set my timing? any info is greatly appreciated.

peckinpah

Usually means your TPS unit is bad or needs to be calibrated.

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

xxxtreme22r

if and when you set the jumper does your check engine light come on an blink? Might not blink can't remember but it should at the very least come on. If it doesn't then the jumper isn't in correctly or something in the wiring is preventing it from jumping properly. If it's on before you start, read the codes first and reset it by pulling the ECU fuse.

pist

Dunno if I should start a new thread for this, but I'll try here first. My CEL flashes when the jumper is inserted, but idle does not change. TPS is new and, as far as I can tell, calibrated according to that guide. I believe some resistances were slightly off, but they were no different on the old TPS. In any case, the resistance changes at the proper throttle position. Without that idle change, the truck runs best with the timing advanced about 20 degrees. At ten degrees, it barely runs.

Engine is a freshly rebuilt 3VZ-e with Downey headers, Weasy2k mild cam specs, and K&N FIPK. The timing problem has been there since before I tore the stock motor down. I've checked the timing belt positioning probably six times throughout this process, and it's always been correct.

The wiring harness is suspect because I believe the previous owner cooked the engine/bay before I bought the truck. Much of it is brittle and I had to replace the fuel injector connectors. However, resistance values from the ECM connector to the TPS connector seem fine. I'm also wondering about the ECM itself, but I have no idea how one would check for proper functioning on that.

Any other ideas?

Thanks

ToyotaViejo

I have just (a week ago) replaced my TPS with the throttle body off the truck. the old one was definitely bad, and I got the new one set up to FSM spec.

I also replaced my o2.

This was done to correct firstly a gassy exhaust and secondly a solid, but erratic, idle.

It worked on both counts.

My fuel economy is horrid (even by 3vze standards) so I've been testing other sensors, etc.

Probing the distributor wires today, I found that both G1 and G2 to G(-) are almost double the resistance spec.

Oddly enough, despite a good idle and working TPS/o2, the jumper does not change idle, and I get the "no code" constant blink.

I'm wondering if a bad signal from the distributor's signal generator (essentially a cam sensor) doesn't preclude the idle step-down.

Have you checked yours?

pist

Mine are within spec (below 235 ohms), although in the ECM section the service manual puts a decimal in front of that 235, for .235 ohms max. I'm pretty sure the first value is correct since someone confirmed it for me in a Haynes manual (or something similar). If it's really supposed to be in the tenths, there is definitely a problem. Otherwise, you may have found your solution while I'm still in the dark.

Incidentally, my primary ignition coil measures .9 ohms when it should be .36 to .55, but I'm not sure how that would be at fault.

I have an unconfirmed hypothesis that the idle step-down happens because we are forcing the engine into open loop mode (not using sensor input to adjust the A/F ratio). This is how a cold engine runs before the O2 sensor is warm enough to provide meaningful readings. If the truck never transitions to closed loop mode then there is no return to open loop, and thus no idle change, when the jumper is inserted. If that were the case you could expect crappy fuel economy, but you would also think the truck should eventually throw a code.

ToyotaViejo

The open/closed loop theory is nothing if not interesting... Other than a bad ECU, what would keep that shift from happening? Is there any way to test that theory?

I've given the FSM a glance and not seen much definitive.

The ohm range for the distributor resistance test is in ohms. Hundreds of ohms, actually, but ohms.

Primary coils on most Japanese vehicles I'm aware of are picky as hell. If yours is consistently testing bad, it's probably bad.

I think that the computer controls idle advance through the coil and igniter, and if your coil is bad, well, that might be your problem.

pist

I guess I'll order a new coil.

Someone who knows early EFI systems would probably be able to say what the jumper is doing and/or why it's not doing what it should. All I've ever seen is "put the jumper in and the idle will change." No explanation why, and no troubleshooting procedures other than the TPS adjustment. The computer would be doing the switching; I don't have a clue how to tell which mode it's in.

ToyotaViejo

I'm running out now to go order a new distributor. At least you can feel good about the fact that mine is pricier than yours...

You might want to run the FSM diagnostics on the signal generator too. Coils like to take out other things too.

You know, I think the coil itself is the same across a whole bunch of Toyotas. Is there a known good one you can borrow to test with before you buy a new one?

pist

Is there something other than checking resistance for the signal generator (we're talking about on the distributor, right)? As I said before, mine checks out fine.

New coil wasn't too expensive, so I bought it just to be on the safe side. I went through the O2 sensor procedures and determined it was worn out (about five deflections in ten seconds when it should have been at least eight), so I replaced that. In retrospect, that probably should have been the first thing I looked at. I installed the jumper to see if it worked and if the idle changed, it was very subtle. I'll have to hook the light up tomorrow and reset the timing. If it advances like it's supposed to when I remove the jumper, I'll call it good.

Did your distributor fix your problem?

ToyotaViejo

Why did I say signal generator? Sorry man, long day. I meant to check your igniter. I know it's in the FSM, but I can't seem to find the page right now. A bad igniter can kill a coil, and a bad coil (I think) can kill the igniter.

I don't know why Toyota sticks to 8 deflections as the minimum. That is even a pretty slow o2, but I'm not an automotive engineer. I know it doesn't make sense for it to cycle faster than the clock in the computer can read it, but...

I ordered my distributor, and it should get here tomorrow. Assuming I don't have to pull all the plugs, get to TDC, etc. and can just line up the rotor to match the orientation, I should be able to get it in tomorrow.

I did a dynamic test on the VAFM which I hadn't done before, and it appears that there might be a few dead spots in the continuity, so I bought a used one from the classifieds here.

I didn't buy a Denso distributor, but I did buy a rebuilt, so hopefully it's of reasonable quality.

Shoot your timing, and let me know if that fixed the problem. I've seen coils do some WEIRD stuff.

pist

So the timing seems to be okay now. I don't know if it was the coil or the O2 sensor, but I don't much care at this point. The change in idle when the jumper is installed really is subtle, and now I can't help wondering if I just missed it before. I confirmed the change with the timing light, though; it moved from 10° to 8° BTDC when I removed the jumper. The motor still doesn't seem totally right. The timing jumps a little every fourth cycle or so, and there is an accompanying surge in the idle (very slight). That mystery will have to wait for later, though. For now, I have to see if this thing will pass the CA smog test as is.

Did you get your distributor?

ToyotaViejo

I got it alright. And it tested more out of spec than the one presently under the hood. So then I went to a Toy junkyard and tested.literally 12 distributors. Every one of them was about where mine is.

I'd think I was testing it wrong, but I following the FSM to the tee. I've even matched up the wires.

If you get a minute, would you take a picture of your harness off the distributor, and run the tests yourself so I can compare mine to yours?

I might try the dealership tomorrow. Problem is that if they have one, it will be in spec and cost $700. At this point, I don't think I'd buy one I couldn't test in advance.

On a side note, I did dial back my AFM two clicks to the clockwise today. We'll see if that helps lean things up a bit.

That's great that you are looking better after the coil. I'd hate to think you didn't need it, but now it's one less thing to worry about.

Your wandering mark could be inductive interference from other wires near the clamp. I couldn't find anywhere to get the #1 wire by itself and free of the right bank exhaust manifold.

pist

My truck is stored about an hour away while I work on it, and I hadn't planned on heading back that way for a while. I'll see what I can do to get out there tomorrow, though. I've got an A/C problem to look at while I'm there.

Not trying to insult your intelligence (which I'm sure will happen anyway because I'm good like that), but just to cover the basics...are you sure your ohmmeter is correctly calibrated and on the right setting? My multimeter has 200-ohm and 2000-ohm settings, and I had to go with 2000 because it conks out on the 200-ohm setting. I also verified my results with a second meter, since I had one available. And of course, using the FSM picture as a guide, G(-) was the uppermost pin on the distributor and I measured the resistance from that to each of the other three pins.

I checked mine while it was sort of warm, so I used the 'hot' resistances for an upper bound. I can't remember how close the values were, though--whether they were within 'cold' tolerances or not. Anyway. Like I said, I'll try to get out there tomorrow.

ToyotaViejo

Oh, please dont't go an hour out for this. It was a PITA request if it was parkedin your driveway.

I'm not offended at all, but, yeah, I'm testing it correctly and with two known-good DMMs.

pist

I was kinda hoping you'd say that.

I would have swapped vehicles once I got the timing right but I didn't want to go a week without A/C. If you're still curious when I head back out there next week, I'll happily grant your request. Still, I can't imagine all those distributors you checked have the exact same problem. A rebuilt should have been confirmed factory specs before it was mailed out, no? Just out of curiosity, what sort of mpg are you getting? I think I was getting about 12-14 before I rebuilt mine.

DeafRunner95

hey anyone got a pic to identify the t1 and e1 terminals in the grey diagnostic box? 3.0 v6 3vze

Gevo

If you guys are still around, can you write about your fix for this problem?