MattFels_93PU

Hey guys, I posted this originally over at ToyotaNation, not wanting to bother you all needlessly with what I hope is a very simple questions. Nobody over there is helping me though, and besides I have big plans for my new truck and they line up better with this site than the other one.

Anyway....

I'm driving a just purchased, single-owner 1993 Pick up, that had 100,000 original miles on it. It's in excellent condition, and ran perfectly for the first week. Then I had a full fluid flush, oil, brake, tranny, t-case, diffs, and coolant. When I took it home I changed the air filter to a K&N, and installed Bosch platinum 4+ spark plugs.

I took it for a drive and it was all good when for a split second, the engine sort of stumbled, hiccupped, as if I was running out of gas. It recovered and drove fine for the rest of the ride.

I didn't notice it that much for a bit, but I've put another 1000 miles on it, and it's become more prevalent. Since it felt like a fuel delivery issue I did the easy thing first and changed the fuel filter.

No change for the better. What's happening? It always happens within 1-2 minutes of starting it up, driving normally for about 1/2 mile to a mile, and then this stumbling, near stalling spell happens, and it usually recovers. Every now and then it stalls, and I restart it while rolling.

After it does this once it doesn't do it again, and I drive it 60 miles round trip to work every day, it happens twice. When I leave home, and when I leave work.

At one point I was sure the CEL came on and clicked off, but it won't come on again, in retrospect I think the truck may have just turned off briefly and caught again which caused the dash lights to come on. I jumped the TE1 and E1 terminals anyway and got no code flashes.

I'm confused, not necessarily worried. It seems to be progressing slowly, but it's hard to say, by progressing I mean, coming closer to stalling, or stalling altogether more than it had initially.

My hunch, based on some forum searching, is that it might be a sensor/ECU thing. What do you think about the 02 sensor, they're 50 bucks on Amazon for Denso's, is it worth a swap just for peace of mind, or do you guys have a better idea what's going wrong in my truck.

Thanks so much.

p.s. I also need new front shocks. I have a 4in. Body lift (as near as I can tell) but one day I'd like to go to a 3in. suspension lift, and 2 in. body lift. In the meantime I want to throw in some affordable shocks. I've read Rancho RS5000's are the way to go. Presumably, with only a body lift, the size of the shock should be stock right? And how tough a job is this, the Haynes manual makes it sound pretty simple to swap them out.

Thanks again for helping out a burgeoning shade tree mechanic.

snobdds

Get rid of the Bosch spark plugs and get Denso's. Replace the Cap, rotor and plug wires with OEM replacements. These trucks like toyota ignition system parts....only.

That should fix your slight miss.

GranVille-4crawler

if all of that doesnt work..... there is a cold start injector on top of your intake manifold. unplug that. it could be it is getting stuck and flooding the engine out for a second. (if thats the type of stubling your talking about). since the cs inj is only used until the engine warms up (and you say it happens 1-2 minutes into the drive) that would be my guess if you've replaced everything else

MattFels_93PU

I'm short on cash right now, but I kept the old plugs, which as chance would have it, were of course Denso's. They were working fine.

I'm gonna go swap the bosch out for the old ones right now, and look into cap/rotor/wires in the immediate future. Like when I get paid.

This is the kind of quick attention you just don't get over at Toyota Nation.

Any opinions about my shock questions?

-matt

MattFels_93PU

Swapped the Bosch out for the old Denso's. Same problem, if anything very slightly worse.

Today it stalled at a light, soon after getting in and starting after it sat for 2 hours in 70 degree sunny weather. It stalled and wouldn't start right up again, it would turn over, and whine, but it took me three or four tries to get it to get up and go. In between the third and fourth try I waited about five seconds. Does this confirm an engine flooding/cold start injector as suggested?

I'm gonna go pop my hood and look for the cold start injector. It's not mentioned in the woefully brief Haynes manual, and I can't even find it discussed in the PDF FSM I downloaded.

Any hints on where to find this sucker? And when you say unplug it, do you mean unclog/clean it, or pull it out altogether, or removed the wiring harness that goes to it?

Thanks guys if you're still listening.

-Matt

GranVille-4crawler

the cs inj is located right in the middle of the intake manifold. has a fuel line running to it and a plug in wire on it. just unclip the plug and try driving. it will hesitate to turn over just so you know since the engine isnt getting the extra fuel. my truck had the same issue, i didnt end up being the injector but it was one on a list of things i checks. here's my thread on it....https://www.yotatech.com/forums/f115...r-22re-208506/

MattFels_93PU

Alright, update.

I unplugged the cs inj. Assuming I found the right thing, it's right in the middle of the 4 fuel injectors, on the engine side, the plug goes straight down into the top, and a fairly thick fuel line comes out the bottom? It looked significantly smaller than the other injectors. There is a possibility it wasn't what I thought it was, but the truck (engine still warm enough from earlier) started right up with it unplugged, and I got no weird symptoms.

Except... the preexisting condition. I pulled out driving normally, and at the same traffic light everything happens at, it stalled. It started up on try #2, and the CEL came on, there was nowhere to pull over, but when I gave it some gas to get it to the shoulder sooner, the CEL went off.

When I got home, I jumped TE1, and E1 terminals and got code 22. Engine Coolant Temperature Sensor signal. I'll do a search of the forum directly.

But does this new info affect anyone's diagnosis?

- Matt

p.s. I read your thread granville, good stuff. It always felt like a fuel issue to me, I just don't know if the alarming consistency of the timing makes sense, but your problem was like that too, so maybe I've got sediment in the tank.

And like you I got lucky, an old dude's babied ride. Almost totally stock, 100,000 miles. Just have to clear this little gremlin up.

MattFels_93PU

I spoke too soon. I didn't unplug the cs inj. I'm pretty sure I unplugged the coolant temp sensor. So that explains the code. Still might be the injector.

I'll unplug that after I eat real quick, and take a ride. I'll try to take a picture, it appears the wiring is all new right there, and there's a female plug that's just dangling, that appears to be spliced to a newish looking plug that goes to the cs inj.

I think this is the problem area, so I'm hopeful.

MattFels_93PU

Yet another update.

I found, and unplugged the cs inj. Leaving the coolant temp sensor plugged in. Test drive. Same exact problems, same time frame. Let's say 1-2 minutes of driving, and hesitation, close to stalling, recovery, CEL comes on, then goes off before I can pull over and check it. But I jumped the terminals again, with the cs inj unplugged and got another code 22, plugged it back in and got another code 22.

Thus far I've pulled codes with everything plugged in, coolant temp sensor unplugged, cs inj unplugged, and in all three instances received code 22. Coolant temp sensor's cost $15.00-$30.00. For that kind of money I should probably replace the thing anyway.

But does anybody have anything else to say about possible underlying causes, or are you all confident that plan should fix it?

Thanks

MattFels_93PU

Just in case anyone stumbles upon this thread with a similar problem

I pulled the coolant temp sensor, and replaced it. Drove it around no issues, pulled my negative battery terminal to reset the codes, and have been driving it for the last few days with no stumbling, and no codes.

So that was the problem, and is a problem no longer.

I hope this helps. And thanks to those who helped me.