Van occasionally won't crank, occasionally won't start, occasionally stalls. Related?

Hello Everyone!
As the title says, my van:
occasionally won't crank,
occasionally won't start when it does crank,
occasionally won't crank right away then when it does won't start
occasionally stalls and wont start

All are very temporary, try again in 1-5 minutes, and everything is fine.

Times when it won't crank:
Turning key makes relay behind radio click, nothing else.
Sometimes after holding key in start position for a few seconds, van will start.
After waiting 1-5 minutes and trying again van will start.

Times when it wont start:
Engine fires once, but keeps cranking.
(Usually)after waiting 1-5 minutes and trying again van will start.

Times the van stalls(and usually wont start)
Stalls while cruising, not necessarily while accelerating or decelerating.

99.9% percent of the time it's fine, but once or twice a week it does this.
Sometimes in my driveway, sometimes in the speed lane of the highway:dizzy:

Starting problem vs cranking problem...

They've happened a few times together, so I have to ask...Could the two problems be related?

Any thoughts?

--Matt

IMHO Toyota didn't do a very good job on our starter trigger circuits. When new these circuits were marginal at best. Now after 20 something years of use, they are even more problematic. As any mechanic will tell you, intermittent problems are the hardest to solve. Any problem that can be duplicated is usually easy to diagnose, but the problems that occur randomly are pretty tough. In most cases we have to resort to the "parts changer mentality" and just swap a component out and let our customers become the guinea pigs. If they come back with the same problem later, then we change another part and try again :dizzy:. When they don't come back, then we either solved the problem or they figured we were incompetent and went somewhere else :lol:. Yeah I know this isn't much help, but what else is there :?: ? I wrote a detailed post on the starter circuit a while back, so read that and perhaps it will help. Here's a link: http://www.toyotavantech.com/forum/s...hlight=neutral

I believe your "cranking but not starting" and your stalling problem to be related to each other but unrelated to the "no cranking" problem. Again we're dealing with an intermittent issue so unless you can figure out how to duplicate for testing, then your back to the parts changer mentality. It could be any number of things, but I'd recommend checking codes 1st. Click here for information on how to check codes. If you have an "ignition signal" code stored in the ECU, then I'd suspect the coil or igniter to be the culprit (coil more likely). If there's no code, and the problem occurs often enough, then you might put a fuel pressure gauge in the system to see what's happening there. It could be a failing fuel pump or a problem with the fuel pump circuit. Good luck and keep us posted on your troubleshooting progress. Tim

Thanks Tim!
I doesn't seem like the two problems should be related. I got stuck at the gas station once. I turned my van off, came back and it wouldn't start. Waited a minute, and then it wouldn't crank! I think that it's happened that way once before, which is why I was asking.

Troubleshooting will be a little tough... Right now my van is covered with a few inches of snow. It's been around/below freezing for weeks, and when I get home it's already getting dark. Not to mention I need my van to commute.

As long as it's intermittent, and it always starts eventually, I might wait for it to get a little warmer(just a little), or at least for this batch of snow to melt.

I'll have to check the codes again. Last time I tried it they wouldn't clear.
Pulling the EFI fuse or disconnecting battery, I'm still stuck with 21 51.
I'm sort of doubting that, all my other tests on the oxygen sensor looked good, and the van runs perfect(when it starts:)).

--Matt

As you know, code 21 indicates a bad o2 sensor and code 51 indicates a bad TPS (both common failures on a 20 something year old van). Still, codes should clear when you pull that fuse. Have you waited at least 10 seconds after pulling the fuse before putting it back in? Try resetting it by disconnecting the van battery for a minute or so, then re-check for codes before starting the van. Having an ECU that won't clear by removing power is an indication of a bad ECU. Tim

Given the stalling problem, a bad TPS is not that unlikely, and in my (admittedly very limited) experience, a TPS bad enough to throw a code will throw it again real fast; ditto for the O2 sensor (though the latter was on an '85).

Neither should affect cranking, however.

FWIW, Skyler has been grumpy about cranking in the cold weather — seems to be something to do with his clutch start switch, but I haven't tracked it any further than that. I pump the brake pedal and the clutch start switch engages the next time; not sure if that's actual cause-and-effect or a placebo.

Gwen

I've had the same exact difficulty on my 88 Auto 4WD. For me, it's not the TPS, O2 sensor, battery, or starter. I did replace all the relays/fusible links under/behind the passenger seat. That drastically reduced the number of occurrences of starting issues. My next step is the ignition switch. When I first acquired my van it had an ignition by-pass switch. I never had ANY starting problems when I had the by-pass. I had it removed, shortly later the problems arose. The ignition switch is the next beast I will slay!

I just want to throw this out there because I see no mention of it, and I just got a new van with a starter switch bypass.
The issue I have found is a bad starter relay and the people I got it from just put a toggle starter switch in.
I have not removed the toggle and probably never will, is kinda nice to have.since
The Relay is a common start intermittent issue on all vehicles, as well is the park, Neutral or clutch start switches.

I know it is the relay because sometimes I just turn the key and it cranks and other times I turn the key and it doesn't.
similar to a bad contact on the starter but with the bypass switch it cranks every time.