I posted this as well in the alternative fuels directory because I'm not sure if the 6.5 group here has much experience with veggie oil conversions.

(http://www.dieselplace.com/forum/showthread.php?p=751759#post751759)

I have a 95 Suburban. It had a touchy excelleration problem which has been getting worse. (Little pedal means lots of fuel - even the cruise control has problems with it) Some thought the ECM... some the IP or PDM. I've found a highly recommended diesel mechanic who has diagnosed it as the IP.

He says the VO coats the optic eye and is confusing the pump. He says it is impossible to run VO in this injection pump that it will fail because of it. He is not familar with VO conversions, mine was the first he saw. He will not warranty a new IP for me. (no big surprise there and I understand this)

I'm hoping to hear from someone who is familar enough with the workings of the IP to give me some insight on the optic eye. My mechanic's sources are saying the same problem is happening with Biodiesel. My gut tells me that he simply is uninformed because I know people have been doing this with this IP for years. However I also need to fix my 'burban...

Thanks,
Bill

Did you move the PMD off the pump before running hot oil thru it?

No... I kinda expected the PMD would go eventually and considered just having the spare remote kit around for when it happened. But there's a big difference in the PMD & remote kit vs a whole new IP and remote kit.

I'm still left wondering how to respond to the optic eye concerns my mechanic has though.

I don't go for the optic sensor alarm. Veggiesuburban ran his truck for over 40,000 miles on straight WVO and didn't have any fuel related problems, iirc. I'm leaning towards the PMD thing.

Depending upon the clarity of the oil will depend if you will have a problem with the optic sensor. Quantum had some issues with his mix when it got too dark. Are you running a heated straight oil, or a blend?

If the optic was getting boogered up, I would think that you might see a code pop up. Do you have any codes pop up at all?

It could be that if the oil you are using isn't as thin as it should be, the pump may be trying to compensate for this "unknown" viscosity. Just a thought, maybe a bad thought, but a thought.... How does it run on diesel? Same?

Cruise control problems can be caused by the PMD. The optic sensor (encoder) can be changed on the vehicle if need be.

I could see the clarity of the oil being an issue...

I did have this problem before converting to VO, I have it on diesel now... it's just gotten to the point that it's really, REALLY annoying. Especially with the cruise control on. The accelerator is really touchy with the slightest touch causing the engine to rev high. Happens most noticeably on highway speeds when accelerating from 2000 rpm.

My VO is heated, seems to be the same clarity as everyone else. The mechanic's claim is that the optic eye is now coated with VO and won't come clean. I find that a little hard to believe.

I assume to change the eye the IP needs to be pulled apart, which doesn't seem like a good option for me.

I do know it is throwing codes, but don't know them offhand. Would have to get them from the mech.

I'm just trying to think how to proceed. I can get a new remote PMD if that doesn't solve it go with a new IP. However I also need some sort of injector controller (?) never heard of it. Apparently my injectors are dumping too much fuel into the cylinder - a seperate issue from the above, but is causing a problem similar to wastegate failure.

The point being apparently my intake is going to be off at some point so I don't want him to take it off twice.

Optic sensor failures almost always trip a code.
FSOL/PMD failures don't always trip a code.

Can you run on diesel again and see if the problem goes away?
That would tell you if the optic sensor is really bad or if its just the fuel your using causing the problems.

I did have this problem before converting to VO, I have it on diesel now...
The accelerator is really touchy with the slightest touch causing the engine to rev high.
Supports my guess that the Fuel Solenoid is the problem
The mechanic's claim is that the optic eye is now coated with VO and won't come clean. I find that a little hard to believe.
So do I.
I assume to change the eye the IP needs to be pulled apart, which doesn't seem like a good option for me.
The Optic sensor can be replaced on the truck, but I don't reccommend doing it yourself, and you will need a scanner tool to verify you got it positioned right.
I do know it is throwing codes, but don't know them offhand. Would have to get them from the mech.
That would help A LOT! If they're 35/36 then you need a new pump because your FSOL is shot. If they're optic sensor related, and your running on pure diesel, then the optic probably needs to be replaced.
However I also need some sort of injector controller (?) never heard of it. Apparently my injectors are dumping too much fuel into the cylinder - a seperate issue from the above, but is causing a problem similar to wastegate failure.
I've never heard so much bologna I don't think, nor have I heard of an 'injector controller' or see how it could have anything to do with the wastegate.

Hopefully he isn't talking to our buddy "steak sauce" marketing the infamous "fuel controller"

I'm just trying to think how to proceed. I can get a new remote PMD if that doesn't solve it go with a new IP. However I also need some sort of injector controller (?) never heard of it. Apparently my injectors are dumping too much fuel into the cylinder - a seperate issue from the above, but is causing a problem similar to wastegate failure.


Injectors are at the mercy of the IP. The FSOL is what determines how much fuel makes it to the injectors. This is a very precise measurement too, once it starts to foul up, you'll get stuff like your getting.

You've got OBD-I anyway, check with paperclip in kennedydiesel.com tech tips.

Gut feeling: fuel solenoid

The optic can't stand water but filtered water free VO shouln't be a problem.

OK... Here we go.

Codes are 36 42 and 78.... But the mech thinks 78 will clear itself with a new PMD (if not we look at the wastegate)

I see that 36 is indicative of the eye or fuel solenoid (FSOL I assume) but I'm not sure I quite understand... is the FSOL *INSIDE* the IP? I'm thinking it is, in which case the mech is correct... I will need a new IP.

Also it appears what he was calling the injector controller I call the PMD. Since he said I could buy my own IP/PMD and bring it to him - because he won't warranty one because I burn Veggie Oil... I'm in the market now for the relocation kit.

I'm going to look around, my first stop is HeathDiesel but will take recommendations.

And one sad last note to show why I am losing faith in this mech... he mentioned possibly replacing all the injectors to help solve the problem. I think he was trying to gauge my reaction. To me that's like trying to sell me the Brooklyn Bridge at this point. I see no need to, but he quickly dismissed it himself when I politely disagreed.

Thanks, Bill

A 78 will not clear with a PMD replacement....sorry.

36 indicates FSOL problems. High Resolution timing issue would be optic (another code to itself).

I kinda wonder 'bout his mechanical understanding of the 6.5. Not his mechanical ability, but just understanding the way that it works....

Sorry...Still having some trouble figuring out... is the FSOL (Fuel Solenoid O? L?) inside the IP? or after the IP?

I've had the same problems before and read somewhere about the ignition switch causing it. I change it and had no problems since! May be as simple as that. I also had mechanics tell me the IP needed replaced.

This from the Kennedy Diesel website leads me to believe that if the FSOL is bad I need a whole new IP right?

"These [DS-4 fuel shutoff solenoid] seldom fail with the exception of leakage. This is not the delivery solenoid nor is it operated by the fuel solenoid (FSD/PMD) driver. The actual delivery solenoid is not a user serviceable part." - JK

Or am I barking up the wrong tree?