So I have a 1987 Toyota 4Runner SR5, 22RE, W56, with towing package. It has 321,000 miles on the body, and 23,000 on a rebuilt motor. I bought this runner 4,000 miles ago. It also has a Pacesetter header, and LCE intake.

When the truck is started cold, such as first thing in the morning, it runs horribly rough. It sounds like it's running on 3 or maybe only 2 cylinders. It will not idle unless I hold the throttle to keep the RPM's up. It will run with the rough idle for anywhere between 15 and 90 seconds, occasionally even longer. Within the past couple days, it's started popping out the exhaust once every few seconds. When it starts clearing up, it's very obvious. I can hear a ticking noise. Something like tick... (2 second pause) tick tick (pause again) tick tick tick tick (pause) then it will run normal. Each tick is followed by what seems like one cycle of every cylinder firing. Also, this hard starting is a lot worse after rain. And within the past day, it's started to skip a random beat when accelerating from a stop, even when warm and after driving for a while.

Here's what I've tried to fix the problem:
Cap, rotor, and wires have 10,000 miles or so
Spark plugs have less than 1,000 miles on them
I replaced the distributor with one from an 89 P/U with 142,000 miles
Original AFM showed many dead spots on the resistor strip. Swapped with an AFM that tested good and no change
Adjusted ignition timing to 5 degrees BTDC with jumpers jumped
Seafoam treatment through vacuum line twice
Fuel injector cleaner along with fresh 87 octane gas (only 20 miles run with injector cleaner)
TPS measures in spec
Disconnected CSI
Intake flex pipes have no cracks
No CEL codes
The fuel injectors were replaced by the previous owner but I have reason to doubt this because the injector bodys are rusty. I doubt that would happen in the 4 years he owned it.

Each item was done separately with a test after. The only thing that might have made a difference was swapping the AFM which made the Runner feel a bit more responsive and quick, but the rough cold starts, and misfire under load are still there.

I plan to do the following:
Block off EGR
Adjust valves
Check for good connections to injectors
Swap CSI with one from a 1989 P/U with 142,000 miles

Any suggestions for what to swap, replace, or test are greatly welcome. I need a reliable vehicle when I'm at school and 200 miles is a long way to walk.

 

If more people were as descriptive as you are. You covered every base I would of thought of. I would suggest adjusting the valves like you said. As hot as it is, I dont think you will get anthing from changing the CSI, but what could it hurt.

The EGR does put alot of carbon thru the system and clogs alot of the ports and hoses off of the Plenum. Might suggest giving it a good cleaning. If you have a lot of carbon build up I suggest just pulling the Plenum and take it to a high pressure carwash. If none of these fix it, I woudnt know. You gotten just about everything I could think of.

 

Knock sensor could be bad....lol other than that I'm clueless unless...the rings they put in in the rebuild are junk...

 

I don't think the rings are bad. It doesn't burn oil, and the oil stays clean. I changed the oil when I got the truck and it's stilll pretty clean 4,000 miles later. I haven't done a compression check.

I adjusted the valves. No difference. They were all out of spec. All were tight and 3 exhaust valves had no clearance so the valves were most likely hanging open. But with the valves in spec adjusted hot it still acts exacltly the same. I don't see how the knock sensor would cause this, it definitely seems like one or two cylinders are not firing when it's first started cold. Once it's warm it sounds like one cylinder skips a beat every now and then. But I'll try disconnecting it and I'll try swapping it.

 

If the knock sensor is bad then it willact up on a cold start and under load as it is trying to lean the mixture out. Now if its skipping like a school girl if check to see if i had spark on each plug and check the gap as well. I've seen some crazy stuff due to incorrectly gapped plugs.

 

I just thought also...you could have a valve sticking that would definitely cause a very similar if not identical problem.

 

I disconnected the knock sensor. It might have ran a bit better but it might have been just me. It threw code 12 which indicates a problem with the knock sensor circuit. I cleared the code and installed a knock sensor from a 1989 P/U. No change. Might have ran a bit worse but it might have been just me again. Engine shows no trouble codes. I adjusted the ignition timing again from 5 degrees to somewhere around 8 or 10 degrees with the diagnostic jumper jumped. No difference.

All these tests were done in the last few hours so I haven't been able to test cost starting. But throughout all the warmed up road tests, it stumbles under low throttle acceleration and low throttle cruising. WOT it runs great. Idle has a miss every few rotations.

Tomorrow I'll shoot a video and post it up to show how it starts and runs when cold and warm.

 

I forgot to say I also checked the CSI. It tested to 3.8 ohms which is withing the 2-4 ohm specification. I then wanted to make sure it wasn't leaking. I disconnected it from the plenum and pulled it out far enough to see the nozzle. I then jumped B+ and FP with the ignition on to trigger the fuel pump. The CSI showed no wetness or leaking after 1 minute of the fuel pump running.

Could low fuel pressure cause the issues I'm having? I have a used pressure regulator off the same 89 motor I'm pulling the other parts off of. I don't think my fuel pump is bad. It sounds healthy and the motor runs fine at WOT. I'm thinking the pressure regulator is acting up causing too much fuel bypass at low load.

I gapped the plugs to 0.8mm when I put them in. It would be worth checking if it was done by the PO or a shop. The valves followed the cam fine when I had the valve cover off to adjust the valves.

 

You might try a new ignition coil too, looks like you replaced everything else in the ignition system. I'd go over the vacuum system again too, these EFI systems are really sensitive to leaks, using the propane torch trick should reveal any leaks.

 

Here's how it started and ran this morning. After revving it in my driveway for a few minutes I pulled out the spark plugs. Number 2 was wet and smelled like gas. So I guess I'm either not getting spark or my injector is stuck open. I checked the spark plug wire connections and they all looked good both at the plug and at the distributor. While it was in the garage I also swapped out fuel pressure regulators. No change as you can see in the test drive. The test drive was filmed after checking the plugs and swapping the FPR.

The ignition coils look the same between 87 and 89 but the ignition module thing on top is different between the two years. I'll try the coil.

Here's the video:

www.youtube.com/watch?v=F7Uc9WsASDs

Here are the spark plugs.

Cylinder 1:
http://i117.photobucket.com/albums/o...2/IMG_1585.jpg

Cylinder 2:
http://i117.photobucket.com/albums/o...2/IMG_1580.jpg

Cylinder 3:
http://i117.photobucket.com/albums/o...2/IMG_1582.jpg

Cylinder 4:
http://i117.photobucket.com/albums/o...2/IMG_1587.jpg

 

Swapped the ignition coil but not the module on top which is called the ignitor. No change. Both the coils and ignitors from each engine have different part numbers. I swapped the coils anyway but like I said, nothing changed. The ignitors have the same color wires coming out of the box but have different style connectors so I can't just plug them in. I'd have to splice which isn't something I want to do unless I know it will solve the problem.

 

Because of the wet spark plug, I'm leaning towards a stuck injector. So I bought one fuel injector and an intake gasket set from Advance Auto. The injector should be in tomorrow. I'll swap that in to replace injector #2 and see if it makes a difference. If it works I'll buy a set from 22RE Performance or maybe get mine rebuilt. If it doesn't work I'll swap the new injector into the other 3 cylinder and see if any difference is made. If it still doesn't work I'll be pissed.

 

My only other two reccomendations would be...

1. Check the fuel pump and fuel filter. They could be cloged or not running correct.

2. IACV under the intake. It may be clogged and not letting extra air into the TB at warm up.

 

I disconnected the wire to plug number 2 and plugged it in to a test spark plug which was grounded to the head. When I started the truck it had the same rough idle as when started cold. If it was worse then that would indicate I created a problem where there wasn't one. But since it was the same, that means cylinder number two wasn't firing anyway. But when I looked at the test spark plug with the motor running, it was consistant. Even when revving the motor the spark seemed to be consistant. Granted, I wouldn't have noticed if it skipped one fire but the point is it was working better than the misfire would indicate.

So I don't believe I have a problem with the electrical system of the motor, I think it's having fuel delivery problems. I guess we'll find out when I get my new injector.

 

I don't have a new fuel filter but I have two used ones. One with 156,000 and one with 142,000. I don't have another fuel pump to swap in. I feel like if either of those were the problem then I'd have issues all the time regardless of whether the motor is cold or warmed up, and the problem would be worse under hard acceleration and high RPM's. It runs good at WOT. The problem when cold is very rough idle as if it's only running on 3 cylinders. And the problem when warm is stumble under load at low RPM and occasional misfire at cruising speed, 45-55 MPH.

Would the IACV only affect one cylinder when cold? And does it have any affect when warm? I'll see if the spare one from my 89 parts motor is good and if it is I'll swap it in.

 

wet plug usually means a) bad spark or b) flooding. You've tested spark right at that cylinder, correct? So that suggests a leaky injector (since it's only one plug). When warm, the cylinder just runs rich, or when the injector warms up it stops leaking.

Swapping in a new injector is one way to test that, but if it was my truck I'd just eliminate it once and for all by having them cleaned/tested. At $21/each it will be cheaper than buying one injector. And if the injector is unfixably bad, the test will tell you that so you'll know you're not guessing when you buy a new one.

 

I agree. But before I do that I just want to make sure the injector is the problem. If replacing one injector cures the problem I'll look into getting them all done. But my priority right now is fix it and make it driveable. If I send out the injectors, I can't drive it, and I won't know if that was the problem until I get them back. The guy at Advance Auto said if it doesn't fix the problem I can return the injector.

 

Check twice; I've never seen a parts supply store that would take back "electrical" parts including injectors. (How would you like it if the "new" injector they sold you had been used and abused a few times?)

But if that's what they'll do, all you're going to lose is a set of crush washers.

 

You could also swap the suspect injector into a different cylinder and check the plugs to see if the wet spark plug is now in the cylinder you moved the potential leaky injector to. It would at least save you the cost of a new injector if that's not the problem.

 

Well I'm happy I figured it out, but I'm upset to find out what it was. I went through the process of replacing the #2 fuel injector which takes 1.5 to 2 hours. After I buttoned it back up it still had the exact same problem. So time well wasted. When the #2 spark plug wire is removed there is no change in the bad idle. So for shiggles I swapped #2 and #3 plugs. The problem now moved to #3 cylinder. So all along I had a problem with a spark plug. Would have been under $3 and 5 minutes to fix.

I guess I couldn't convince myself a plug would be bad after less than 2,000 miles. So lesson learned is when you have a problem of any sort, spend the $12 on new spark plugs whether you think you need them or not.

Now I gotta reinstall the fuel injector that was in the truck so I can return the new one. That's tomorrow's project.