This refers back to my original thread here: https://www.yotatech.com/forums/f2/3-4l-swap-wont-start-ignitor-84436/

I am ready to start pulling my hair out! It is driving me crazy!!!

A little background: I have a 1994 M/T 4Runner that I am doing a 3.4L conversion with from a 98 4Runner M/T donor. The engine is in and I have been trying to get it to start for months and I am at my wits end. I am using a ORS 3.4L conversion harness for the wiring duties. As of right now the exhaust still needs to be fabricated. I am using Downey headers. Temporarily I installed the O2 sensors to close the circuits although there are about three or four other connectors at the same end of the 3.4L wiring harness that are not being used. (should they be...and can this be my problem??).

I am getting air and fuel but I am only getting spark at ONE of the coil packs at the #1 position (front right cylinder). All the coil packs work because I can rotate the coil packs and get the same result only at this #1 position.

I have been throwing too much money at this and have replaced to date: Igniter, ECU and plug wires.

Tested the crank and cam position sensors and they both fall within the FSM recommended Ohm readings (cold). I am beginning to guess that, even though these test out ok the problem lies within one of these sensors.

 

Is it possible for you to tell us which "plugs" are not plugged in yet? That might help a little, even though it's pretty strange that only one coil pack (position) works. Are you sure the ECU is good?

 

I'm going to throw this out there just in case. Did you replace your timing belt and maybe you should check the timing marks in case you havnt done that yet.
I'm sure the cam and crank sensors tell the ECU when to ignite the coils. One more thing maybe get the FSM for your truck and follow the trouble shoting flow chart for a no start situation.
I can send you some PDF files if you need . PM me with your email Addy if you want the files.
Two months and no start you must have the patience of a buddist munk
Oh yeah about the plugs hanging by the 02 sensor I've done the swap and have several unused plugs haging there as well I think they are for the trany used in the 3.4

,Thomas

 

I am not completely positive the ECU is working although I did replace the ECU with another from the same year Tacoma.

 

I did not replace the timing belt. But that is definately something I will look into. I have the FSM for the 98 4Runner and I have followed the no start troubleshoot section. This is the reason I have replaced and tested the parts I have done so far. The crank and cam position sensors tested withing the factory specs according to the FSM.

I don't know about Buddist Monk but I mainly work on this during the weekends because I have been going to school full time and working full time and the rest of the week my son takes up my free time.

 

Sorry to hear about your problem. Did the engine run ok before it was removed from the donor truck? You say "the exhaust still needs to be fabricated", so how do you have the O2 sensor in place?

 

I have the O2 sensors plugged into the conenctors and that is it. I was thinking that I would still get spark at least if the O2 sensors are not installed in the exhaust tubing.

 

I would think so too. Did the engine run ok before it was removed from the donor truck or do you know?

 

I bought it from a wrecking yard out of state....so unfortuately no, I don't know.

 

For the record Pozi I was able to start my motor without the oxy sensors plugged in. You will be able to run it for a few minutes before it goes into closed loop mode. The ECU will throw a CEL if you run it to long.
Wish I was there to give you a hand at getting that motor running. Let us know if the timing marks line up.

,Thomas

 

Yeah the vehicle has been down for over a year now! Thank God we have alternate vehicles.

 

You do deserve a medal for patience but at least your spending quality time with your son (I can certainly relate to that since my little guy gladly gets the better part of my day after work).

I still get the feeling there is something that might be wired up incorrectly (the fact that only one coil pack is firing is very strange). Are you sure that ORS made the correct harness for your engine/ECU combo (since the pinout on ECUs changed from year to year)? Have they given you any help on troubleshooting the issue at all? I mean without knowing if the engine ran and with a custom made engine wiring harness the possibilities seem almost limitless. You mentioned already that you went through all the sensors so I am also curious about the timing belt alignment (just pull the top cover off and verify the cams against the crank pulley).

 

Ok. No luck with anything.

I tore the front of the engine off to double check the timing marks. Everything is ok there.

Checked the continuity between the coil packs and the igniter. All ok

Continuity between igniter and ECU. All ok

After looking at the engine wiring diagram for the 1,001st time it is a mystery ar to what the iginter does exactly.

I am at my wits end here.

 

Pozi, you are in a very difficult area for most people and wiring issues can be particularly frustrating. It is going to be a very time consuming process to find the culprit for your no start condition but do take anything for granted (including the fact that the ORS harness is wired correctly), you'll need to double check it all. You might even need to get a second ECU for testing and perhaps a second harness from that same truck to make thing easier for you to adjust rather than them being right in the truck. That way you more or less know everything will work together and it is pinned right. I still don't think this is an ignition issue at all since there are other sensors which can cause a no fire condition too.

Here are a few more helpful links for you:
http://www.pirate4x4.com/forum/showt...5&pagenumber=1
http://www.4x4wire.com/forums/showfl...=&fpart=1&vc=1
http://www.4x4wire.com/forums/showfl...5&o=14&fpart=1

 

Thanks for the reply and those links. I have read all of them many times in the past.

 

Sounds no good. Where you located at Pozi? Maybe someone local could be of some help.

 

Have you tried calling Mike @ORS?

 

I threw them up there just in case.

I would definately give ORS a call and see if they have seen this issue in the past.

 

I am located west of Seattle. Poulsbo, WA.

 

'Sorry I don't have a '98 electronic FSM. This is from my '00, so just use the terminals as a guide.

Check for 12v on one side of each coil.

When checking for the pulses, ordinary multimeter should show the pulses as noise (something other than a flat, stable voltage, a meter with a hold function will record high/low readings, a scope will show the waveform.

If the #1 plug is firing, the #4 plug should be firing also, does it?

Does the #1 plug fire just once, or continously thru cranking?