Need 1st gen Jedi's help... throttle bog & backfire

[TOY2G]

I have been searching here and yotatec all morning. I thought I was on to something, but in the end it was just an exercise in futility.

I have an 87 with new top end (NEW not reman) that I just went and picked up in TX. I drove it all around when I was there with no issues (other than it will not start without starting fluid if it sets from more than 10 min)

I trailers it back to Ohio from TX and when i went to back it off the trailer, they key did nothing. No crank. So I rolled it off the trail and stuck in in the shop. The next day I tried to start it and it fired up (with starting fluid) no problem. So I took it for a drive, as soon as I popped it into gear it started shaking. every time I hit the gas it just bogs down and even backfires (intake backfire) and I could not get over about 3mph.

I pulled it back into the shop, shut it down and popped the hood. went to start it again and when I first turn the key, I get nothing. But if I hold it in the start position for about 2-5 seconds it will start to crank.

once running, if you open the throttle it just bogs down and pops in the intake like a backfire.

What could have happened on the trailer or in general that would cause this?

every part of the top end is new (400 miles new)
cap plugs, wires and rotor all new (BWD)

I sprayed carb cleaner all over (safety 3rd) with it running and could not find a single vacuum leak.

FWIW i cannot get the idle above 750RMP even with the screw backed all the way out.


IDEAS?

Ready........GO

 

[KidVermicious]

Sounds like you've got your work cut out for you.

On no-crank issue, you need to do some troubleshooting, but I suspect the relay. It's a common problem . Next time that problem pokes its head up, run a jump wire from the positive battery post to the crank wire terminal on the starter. If that cranks the truck, your starter and battery and battery wires are good, and you'll want to see the above thread. If your truck has a factory starter relay, follow RAD4Runners' link in that thread to a better fix than mine - if it doesn't have a relay, do what I did.

As for the other, I'm just guessing but funky idle speed and popping in the intake sounds like timing. The disty could have shifted on the trailer ride, throwing your timing off?

 

[TOY2G]

The disty could have shifted on the trailer ride, throwing your timing off?

Never thought of that, I will have to check the timing.... It does act like a timing issue, but if you build the RPM slowly (in park) to about 1500RPMs then it runs fine and you can floor it with no lag.

Im going to go mess with the relay now and then check the dist.

 

[KidVermicious]

It does act like a timing issue, but if you build the RPM slowly (in park) to about 1500RPMs then it runs fine and you can floor it with no lag.

THAT sounds like a fuel issue.

 

[TOY2G]

THAT sounds like a fuel issue.

Well I reset the timing, I could hardly tell when I jumped TE1 & E if there was a change in idle. but i capped the advance, and set the timing to 5 degrees. Now I get a CEL "11" something about power to the ECM. so its looking like this is going to get more involved than I had hoped.

The TPS was sticking partly open, so I pulled it and cleaned it with MAF cleaner. now it snaps back like it should. so next I start chasing wires to find the cause of the "11".

as of right now, it will start (with starting fluid) and idle just fine, but any amount of throttle will just choke it out. I cannot even really build the RPMs slowly even anymore.

 

[KidVermicious]

This truck is running you all over the place, isn't it? No change in idle when you jump the test ports normally points to a bad TPS signal, and a code 11 on an '87 is

"Short circuit in Check Connector T with A/C switch ON or TPS - IDL point OFF
- Defective A/C switch
- Defective TPS circuit
- Defective TPS
- Defective ECU."

Try calibrating the TPS

There's two different sets of OBD codes for 22RE trucks by the way, early and late, and '87 is the last of the early set.

 

[TOY2G]

This truck is running you all over the place, isn't it? No change in idle when you jump the test ports normally points to a bad TPS signal, and a code 11 on an '87 is

"Short circuit in Check Connector T with A/C switch ON or TPS - IDL point OFF
- Defective A/C switch
- Defective TPS circuit
- Defective TPS
- Defective ECU."

Try calibrating the TPS

There's two different sets of OBD codes for 22RE trucks by the way, early and late, and '87 is the last of the early set.

Thank you for the direction, I will start there. And should I ever see you, I owe you.

this thing is driving me nutz.

 

[KidVermicious]

And should I ever see you, I owe you.

Nonsense. I've been helped plenty of times on this board, and I've seen you helping others too. Nothing is owed.








Although if you really wanted to settle the debt I'd be happy to review one of those KTT soft tops for ya.

 

[TOY2G]

Although if you really wanted to settle the debt I'd be happy to review one of those KTT soft tops for ya.

I happen to be out of the KTT tops at the moment. But PM me and I would be happy to hook you up with something.

I ordered a new TPS. I removed mine and when you open it, it does not close back all the way unless i push it a little, and a couple times it stuck open all the way. I will replace it when it gets here and continue trouble shooting.

When you say defective AC switch, are you referring to the switch in the HVAC controls? I have a spare on of them someplace.

 

[KidVermicious]

When you say defective AC switch, are you referring to the switch in the HVAC controls? I have a spare on of them someplace.

I don't know for sure, but I suspect that's referring to the AC idle-up switch on the motor, as opposed to the physical switch on the dash. I've never had functional AC on one of these, so I couldn't tell you exactly where's it's at or how to troubleshoot it. It sounds like you found a defective TPS though, so that's good. Make sure you calibrate it before you put the new one on.

I'll probably hit you up about a KTT once I've got my silly truck running. It won't do me much sitting in the driveway. :doh:

 

[TOY2G]

Question... I ordered a new TPS even though my old one testes okay (based on the chart in the link you posted for me).

However my new TPS (OEM Part Number 86452-20050) tests only 1.2Kohms @00.57mm. I know it says it should be less than 2.3k (my old one is 2.1k) but is 1.2 too low?

Sorry to bother you

 

[KidVermicious]

No bother at all. I'm no expert, but my understanding is that that's an on-off threshold - as long as you're under 2.3k at that point then you're good.

 

[crash813]

Wrote a whole bunch of advice then realized I didn't read the entire thread very well....ugh.

I would make sure your throttle stop screw is adjusted correctly. Would also agree the new TPS reading should be fine.

Good Luck and try not to get to frustrated. Stuff like this is why not everyone can drive a classic!

 

[TOY2G]

[MENTION=49649]KidVermicious[/MENTION], i have a 4runner to sell you.....
I calibrated the new TPS and installed it, along with some new hoses on the throttle body as well as a new TB gasket.

I started the engine (had to use starting fluid again outside air temp aprox 52 degrees) and let it get warm. then I capped the vacuum advance hoses, jumped the two wires to set the timing (good news is, this time the idle dropped down when i jumped them) and set the timing to 5 degrees.

I plugged the vacuum lines back in, pulled the jumper and the truck idles great, a little low about 700 RPM with the idle screw all the way out but it sound great.

HOW(frigging)EVER, it still falls all over itself when you try to give it any more than 10% throttle. And WOT...forget it.

It no longer has the "11" CEL so it looks as if the TPS was my problem...

Should I replace the fuel pump at this point in your opinion?

I have the intermittent no crank no click that you did a thread on, so I will be doing your mod very soon, but first I want the darn thing derivable.

I am about to order a fuel pump, but thought I would ask your thoughts first.

Thanks again man for the help.

 

[Hyde802]

I would check fuel pressure before replacing the pump.

Have you checked timing? or possibly the AFM.

What do the plugs look like? Do they look like there is fuel building up in the engine?

Ran when you drove it in TX right? Strange...

 

[nevada]

I would check fuel pressure before replacing the pump.

Have you checked timing? or possibly the AFM.

What do the plugs look like? Do they look like there is fuel building up in the engine?

Ran when you drove it in TX right? Strange...

yes, even tho replacing the pump is easy, due to the access panel, TEST the pressure first.


also, have you disconnected the battery, or pulled the EFI fuse recently? it might be a good idea, just to reset the system. these systems don't react nearly as quickly as newer stuff, and work better once everything is cleared.

 

[KidVermicious]

A bad TPS and still doing the other thing, huh? You picked a winner. And I don't want it.

Ok, let's back up. First, what vacuum advance hoses? This is a 22RE, right? I don't remember a vacuum advance, the ECU handles that on the fuel injected motor. If this is a 22R, then maybe there's something going on in the carb? I've never had a 22R and I suck at carbs, so if that's the case somebody else is going to have to step in.

Assuming a 22RE, let's check more stuff before replacing the fuel pump, because in my experience these fuel pumps either work or they're dead. I think you need to check again for a vacuum leak, and verify that your timing is still where you want it. Then let it idle until it's good and hot and then see if it's still acting up, if so that should rule out the IAC and it's temp sensor. Look for unmetered air coming in after the AFM, the boots on the intake tube are known to crack in the accordion sections. For that matter, check the signal off the AFM too - you can't calibrate it the way you can the TPS, but it's still a POT and you can check the resistance sweep as you move the vane inside the AFM and make sure it's within spec. If the AFM is good and there's no air leaks, try popping the AFM off the filter box and spraying starter fluid through the AFM while you rev the motor - if that evens it out for a few seconds, then maybe you do have a bad fuel pump or clogged filter. A fuel pressure test should help point that out though.

If none of those point to a problem, then I'm running out of ideas. Maybe a clogged cat? Bad EGR? Gremlins in the wiring?

 

[mikekfr]

Interesting read, clogged fuel filter or clogged cat would explain the lack of power. Gonna keep an eye on this thread to learn the cause & cure myself.

 

[TOY2G]

A bad TPS and still doing the other thing, huh? You picked a winner. And I don't want it.

Ok, let's back up. First, what vacuum advance hoses? This is a 22RE, right? I don't remember a vacuum advance, the ECU handles that on the fuel injected motor. If this is a 22R, then maybe there's something going on in the carb? I've never had a 22R and I suck at carbs, so if that's the case somebody else is going to have to step in.

Assuming a 22RE, let's check more stuff before replacing the fuel pump, because in my experience these fuel pumps either work or they're dead. I think you need to check again for a vacuum leak, and verify that your timing is still where you want it. Then let it idle until it's good and hot and then see if it's still acting up, if so that should rule out the IAC and it's temp sensor. Look for unmetered air coming in after the AFM, the boots on the intake tube are known to crack in the accordion sections. For that matter, check the signal off the AFM too - you can't calibrate it the way you can the TPS, but it's still a POT and you can check the resistance sweep as you move the vane inside the AFM and make sure it's within spec. If the AFM is good and there's no air leaks, try popping the AFM off the filter box and spraying starter fluid through the AFM while you rev the motor - if that evens it out for a few seconds, then maybe you do have a bad fuel pump or clogged filter. A fuel pressure test should help point that out though.

If none of those point to a problem, then I'm running out of ideas. Maybe a clogged cat? Bad EGR? Gremlins in the wiring?

It is a 22RE, I should have started with that. It does have a vacuum advance on, just behind the distributor. I let it run for nearly 40 min and it did just fine. Put the timing light back on, jumped the pins, and capped the vacuum lines and its sitting right at 5 degrees.

I guess I will check the fuel pressure, then I will find the specs and test the AFM. I have heard that you can (even should) adjust the AFM to make it more rich due to the change in fuel the last 30 years. I have not tried it yet, but I am considering it. There are vids on the tube.

I will let you know what I come up with, if for no other reason, so the information is out here for other folks.

Interesting read, clogged fuel filter or clogged cat would explain the lack of power. Gonna keep an eye on this thread to learn the cause & cure myself.

I will go over the entire thing when and if I ever get this thing going well.

 

[TOY2G]

I would check fuel pressure before replacing the pump.

Have you checked timing? or possibly the AFM.

What do the plugs look like? Do they look like there is fuel building up in the engine?

Ran when you drove it in TX right? Strange...

I have not checked the fuel pressure ( i lack the gauge). I replaced the plugs when we did the head (less than 300 miles ago).

I set the timing exactly right, but I have tried advancing it a bit, and it helps the idle but not the bogging.

In Texas it ran like a top, it was gutless because of the transmission but it ran and drove great. I'm wondering if the starting fluid messed up the AFM at some point.

All of this started as I was backing it off the trailer the day we got back from TX.