3100 to 3500 swap not Going Well - help

[malibuRick]

I recently purchased an Ext Crank Sensor to put on a 3500 that I dropped into a 99 Malibu that orig had a 3100. I fabricated a plate for the ORIG 3100 TB (before I found this site and I also rewired the MAP senosr and used the existing 3500 one. I also changed the EGR vaccum plug to use the 3500 set up. Extended the Water Temp sensor to the one in the HEAD. I used a new CAM SENSOR (3100 style to match wiring) under the PS Pump. I also swapped the HARM. BAL and installed a new 24x sensor behind the Balancer since I had it off. I used the 3100 IGNITOR/Coils, fuel rail and all other sensors and wiring harness. All that to just ask why it may not be running smoothly. It is difficult to start, sometimes feels like it is backfiring. I have adjusted the 7x external trigger from 0 to 7 BTDC and it still runs ROUGH. I get codes from ECU stating MALFUCTION with IGN CONTROL module or misfire. IDLE tends to migrate between 1k and 3k (always ROUGH). I replaced the IAC hoping to help, no diff. What is the GAP on TRIGGER I should have. Currently at .40 MM. What DEGREE is recommended ( 0 ) per the guide on the bracket? Is the 7x sensor TOO CLOSE to the HARMONIC BALANCER do I need to use another washer to push it out further to the EDGE of the wheel (maybe it is too close to HARM BAL??). Is the CAM different on the 3500 so the CAM sensor is not FINDING TDC. I have searched the site and reviewed all of the conversions, can you suggest anything on what I have overlooked to make the 3500 work in the 3100/Malibu? Do I have the EXT CRANK TIGGER installed correctly. I even swapped the IGNITOR for a new one and no difference (luckily the took it back .

When it runs, it feels as if one cylinder is missing really bad - engine shakes badly. I put stobe on and point to the EXT WHEEL of the new trigger set up and it jumps around alot. Strange thing is I am on #1 wire and expect the DOUBLE notch to stobe next to the sensor but it is actually OFF by a NOTCH. STRANGE, from best I can tell from Looking at the 3100 crank, the double notch indicates TDC for #1( and 4). Could be normal but did not think it would fire that much BTDC, but I have never used one of these EXT TRIGGERS and this could be normal.

Also it appears the ECU is cycling all the sensor. The AC clutch kicks on and off sporadically (even though the FAN/AC are off). I hear a DISTINCTIVE CLICK but cannot make out from where (not the AC CLUTCH - some other click) and engine almost dies and then recovers and runs enen rougher for a bit. When I am sitting in the car, it appears the BATT light will flash on and off when this CLICK happens. About 50% of the time, the click will cause the engine to immediately Die and backfire.

Can someone provide feedback on what the 24x sensor manages. Even though NEW, could it be bad. Is the woodruff key oreintation on the crankshaft different on the 3500 then 3100 therefore the 24x is off cause the HARM BAL is not positioned correctly. (the site forums say just SWAP the HARM bal. so I assume they would be the same):confused.

I am using the 3100 wiring harness and ECU, do i need to change it out for something else?? The install was easy as all the SWAP forums indicate but getting it to run correctly has me dumbfounded and needing some help.

Thanks
Rick

[CNCguy]

Rick,
We make the External Triggers and each one is assembled using an engine for a fixture. It should work just like stock when set to "0". The timing jumps around a lot if the engine is not running smoothly. The ECM constantly changes timing based on vacuum, RPM and other parameters.

Your gap of .4mm is fine and the location relative to the dampner should be correct if the supplied washers were used. The sensor should be in the middle of the trigger wheel. You could add some washers if it is off center. Is the dampner is completely seated against the crank?

Keyway location is the same on all 60V6 engines.

I will gladly exchange the complete unit if you want to send it back. How long ago and where did you buy it?

IIRC... the engine will run with the 24X and cam sensors disconnected. You may try unplugging them to see if it changes anything.

On a side note, the 3100 TB and injectors are pretty small for that engine. It should run but not to its full potential.

If I can be of any help please feel free to email me.

[Superdave]

Yep, i'd unplug the cam and 24x crank sensor and see what it does. Set the 7x sensor to 0.

are you sure you have the plug wires all on right?

[malibuRick]

Tried 24x senser

Well I tried unplugging the 24x sensor. No difference (other than TACH did not work I then tried the MAP sensor, not change. The the EGR, no change. So going to yard to find a used pack of COIL and IGNITOR. I tried a new ignitor, but no difference but going to try all new coils. See if that makes a difference.

[malibuRick]

I was also thinking about the old 3100 injectors and Fuel rail. Is it possible to swap the Fuel rail and injectors for the 3500. I was curious as there is no return line in that set up and wondering the affect on the orig fuel pump set up. Would it cause damage to the fuel pump or anything. I assume I would need to plug the old return line, but can I just plug into the Original FEED line and everything work OK, or do I need to change alot of stuff. I will have to splice the injector plugs in the 3100 wiring harness, given

[PCGUY112887]

I wouldn't bother trying to use the 3500 fuel injectors and/or rail. Easiest thing to do is to get some injectors that are bigger but still plug in. I use the 3.4 DOHC injectors... they are #24 stock I think... but that is at 45psi and I am using an 00+ FPR which is 55psi giving me a bit of a boost.

With the cam sensor... I used my 3100 sensor in my 3500, but I also have a cam from here. I believe the markings for the sensor were different between the cams... need someone that knows for sure but you may need to use the 3500 sensor and wire it up.

Is the clicking maybe something overloading the electrical system, causing the alternator to kick off (the click) then your battery light come on? Something may have got shorted in your ICM or something not plugged in right, since you say other electrical things like the AC Clutch goes wild.

How did you attach your AC compressor to the 3500 block?

[SappySE107]

The cam recultor wheel is different but it reads the same through the sensor. Did you do a compression test to make sure all the cylinders are sealed? Vacuum leaks?

[malibuRick]

still rough

Well, I replaced the ICM and COILs with a used set up from a 2002 Malibu. No difference. Difficult to start, backfires or stumbles on some compressions. Once I do get it started, it tends to run smoothly at 2K RPM but only stumbles (misfires) periodically. I tried a used ECU also just for grins, it would not even start so I dont think it was good.

I have used a vaccuum gauge throughout all the trials and it tends to stay in the range of 15-20. No jittering or radical swings or jumps. Well until the engine Dies .

You asked about the A/C - the top two aligned, the bottom was a little tricky and does not go to the block (would break the bracket) but keeps the compressor in place.

The misfire does appear to be Electrical but I am dumbfounded on where it may be. The wiring harness changes I made were the EGR vaccuum, two wires,can really screw that up. The MAP sensor and pretty sure I got the 3 wires correct, but the RESITANCE in the 2005 MAP is slightly higher than the orig 1999 MAP, but it is not throwing any codes and when I unplug, I notice no difference in the engine. The Water TEMP, extended the wiring to reach but the TEMP GAUGE and FANs work. Then I extended the CRANK 7x plug to reach the EXT TRIGGER setup.

New stuff
7x
24x
Cam Sensor.
IAC (thought this may be bad - it was frozen and would not move)
new plugs / wires
starter (10 year old one so Hey, why not get a new one
Alternator and Battery tested fine at parts store.

I did not do a compression test and the rough running appears to be more ELECTRICAL - run fine and then BAM - misses hard. Engine only had 30K on it.

So since I have exchange all the possible ELECTRICAL issue I can think of, that is why I was asking about injectors. IF one or several were not working would think it may do something like a HARD stumble or BACK fire. No Gas, no spark, and at higher RPM, one miss it not as noticeable. But at low RPM a miss is felt hard. I got the car as the previous owner was having issue and when I got ($400) discovered BOTH head gaskets were gone. I had a few spares and put them on. It ran so assumed it was good. But I did not put Antifreeze in to test, in a few Days the TEMP dropped to 20 and froze and cracked the block - found a good 3500 that I thought would be better than the orig 3100 and at a third of the cost for a newer engine.

so have ORIG INJECTORS, ORIG MAF, ORIG TPS, Orig TB. All I think may contribute to a bad idle or rough running.

Open for more feedback to get the baby on the road.

[CNCguy]

Something to check. When you extended the 7X CPS wires did you get them crossed? Also, did you twist the extended CPS wires? I can't remember the right amount off hand but it has to be twisted so many turns per foot or the wires can pick up noise. Either of these can cause misfiring.

[Joseph Upson]

Something to check. When you extended the 7X CPS wires did you get them crossed? Also, did you twist the extended CPS wires? I can't remember the right amount off hand but it has to be twisted so many turns per foot or the wires can pick up noise. Either of these can cause misfiring.

At least 9 turns per foot, I just discussed discovering that after an abnormal CPS tracing on the oscilloscope and seeing the notation on a wiring diagram after a harness clean up and code change. Instead of a sharp peak there was more of a slide into a hill appearance. The fuel injector wires and speed sensor wires should be twisted together also to reduce the chance of electrical interference.


Off topic, CNCguy

the 3900 runs superbly with the camshaft fully advanced and it resulted in my idle vacuum increasing by 5 points to the normal ~18 inches of vacuum from the previous ~13. The cam retards also when the module is energized resulting in a momentary drop in idle rpm and a change in the exhaust note.

Hopefully I'll have video up by the end of the day.

[Joseph Upson]

MalibuRick back probe your harness sensor plugs to the PCM plug and against ground to make sure there are no shorts or misconnects. You should also look at your spark plugs and insure you have the proper grounds (I ruined an engine because of that). There is a misfire diagnostic flow chart for this kind of intermittent problem as well. A datalog would help also. Make sure you have good plug wires also and that they are not laying across each other where possible. Rev the engine in the dark and see if you can identify in sparks from ignition parts.

[malibuRick]

Wiring

Dude, did not know about the twist and I assume it may need the exact gauge to ensure proper flow if the TWIST makes that much difference. Any idea on what Gauge of wire to use. and if I did get them reversed does anyone have a PIC of the plugs and what wire goes to which in each side. I will replace the wire end to end, I spliced into it last time to extend. But since this seems to cause some issues, I will replace the whole thing and twist 9 times per foot

Once I do this I will try the other items, GROUND (assume you mean the Engine ground and those are in place on each side of Engine to TRANNY bolt.
Are there other grounds. Plug wires are all new and separated best as possible with the clips and such.

Thanks
Rick

[CNCguy]

Rick,
I would stick with the same gauge wire. Sorry but I have no idea what size it is. I believe the stock setup has the yellow wire going from CPS "A" to ICM "A" and a purple wire connecting CPS "B" to ICM "C". The "B" position on the ICM connector is not used. I have had good luck extending them using the same gauge wire usually taken from an old wiring harness. I always solder each splice and seal it with heat shrink tubing.

[malibuRick]

Rewired

Well, I rewired the CPS plugs with 18 Gauge, looked close and 9 twist per foot. Not much difference at first but seemed to be getting better. Maybe ECU was learning more. It was late and did not want to bother the neighbors so I packed in (just had to try it). Will Try it again in the morning.

[Superdave]

your CPS wire is most likely the problem, replace it with a stock GM piece.

You have to get creative but a stock harness from a 3400 will reach the coilpacks if they're mounted in the stock location. If you need pics let me know.

I had an extended one, due to the difference in wire, length and any other resistance changes i lost about 20 degrees of spark advance and had a hard time getting into the 14's in the 1/4 mile. With no other changes but a stock GM harness i ran a 13.1 the very next time.