Engine/Transmission (1998.5 - 2002) "Limp" Mode

[s2Mumford]

My truck has gone into "limp mode" three times since last Friday Night.

Symptoms:

No engine power, will mosey along at about 15-30 mph, slowly accelerating.

All three times, it was the first start after letting the truck sit for a while.

All three times, it cleared itself up. Twice after turning the truck off and restarting, once, it just gradually cured itself.



Can someone please post a troubleshooting list for me?

 

[Hohn]

This one is out of my league... I hope someone will chime in and help.



JLH

 

[terrywerm]

Mumford,



I had something similar not too long ago, and it just happened to be about a month after my lift pump had failed and had been replaced. Naturally I assumed that my VP was going south. I made an appointment at the dealer to get the documentation process going (still under warranty) so that my complaint was at least registered, even if they were unable to duplicate the problem.



Mine would act up like that for several blocks, missing, running rough, no power, lots of blue smoke, especially after sitting for about 6 hours or more. Sometimes it would start to do it out of the clear blue, even with the engine up to temp. Every time it would do it, I would make a mental note, then write it down once I was stopped and it was safe to do so.



I changed the fuel filter, drained the separator, disconnected my high idler, all the usual stuff in an attempt to rule out any other possible causes, and I met no success.



The solution was actually very simple. I started checking where I had bought fuel for the last few weeks. Lo and behold, I had purchased fuel each time at the same place for 3 weeks, except once, where I tossed about 15 gallons in at another station. During that period, it ran better, but would still go into limp mode from time to time.



I was fairly low on fuel at this point, so I stopped to fill the tank, but I stopped at a different station. Viola! Ran like a charm. Since that time I have fueled everywhere but the station where I purchased the bad fuel, and the problem has not occurred since! Oo. Naturally, I canceled my dealer appointment.



I don't know for sure if your problem is from fuel or not, but I would certainly give it a try. The place where I got the bad fuel is a truck stop - they sell LOTS of the stuff, so I did not expect any problems from the fuel. A friend of mine with a 12 valve gets fuel there all the time and he hasn't had a problem. . My fuel pressure has been right up there where it belongs the whole time too.



The next step I need to take is to go back to that truck stop and put some fuel in from there and see if the problem comes back. If it does, I'll go to the OTHER truck stop across the highway, even though it's harder to get in and out of, and won't go back to the bad one again.



Good luck!

 

[Huff N Puff]

We Need alot more infomation to help

I'm assuming the trans is starting in 2nd gear. If thats the case the trans computer is seeing a problem in the system. You will at least, have to get codes. Turn the key off and on 3 times then watch the odometer. If you can, use a scanner to get codes and infomation. Please post the info. so we can try to help. Merv

 

[Beast2B]

The dealer's OBDII code reader (and most of the better aftermarket units as well) will take a "snapshot" of your ECM/PCM when the trouble occurs. It will indicate any parameters that are not normal; MAP, APPS, IAT, etc. This info should help you (or someone here!) troubleshoot the issue further.

Good luck, those intermittent troubles can really SUCK!!

 

[csutton7]

it will go out of limp if you turn the key off and then back on--it won't fix the prob, but you can at least get it out of limp for a short time--and you can keep turning it off and on if need be--chris

 

[s2Mumford]

Re: We Need alot more infomation to help

Originally posted by Huff N Puff

I'm assuming the trans is starting in 2nd gear. If thats the case the trans computer is seeing a problem in the system. You will at least, have to get codes. Turn the key off and on 3 times then watch the odometer. If you can, use a scanner to get codes and infomation. Please post the info. so we can try to help. Merv

Hi Merv

The stored codes are 1693 and 0216.

 

[mbrolin]

If I"m not mistaken there are 4 items which will put the engine on limp mode. They are related to the MAP sensor,IAT sensor,the injector pump fuel temp sensor and the injector pump itself. The injector pump can throw quite a few different codes and I think 0216 is one of them. I recently had my engine go to limp mode and it ended up being the MAP(boost)sensor. There may be other codes which put the engine on limp mode but these are the ones I"m aware of.

 

[s2Mumford]

Right, I'm just waiting for a Cummins guru to post a comprehensive troubleshhoting list to give me a roadmap to work from.



I'm a semi-competent wrench, but this is my first diesel, and I don't know where to start looking for the problem.

 

[WTBurke]

Stu... do a search on 0216 and 1693. You'll find the bad news. Your VP-44 is going south and it will get worse until your on the side of the road. I am there now... . my rig is in the service center receiving a new VP-44. I lived with all the same symptoms you have for over two months and 4 thousand miles. It got so bad it wouldn't start after warm up



Sorry to be so uplifting



William

 

[s2Mumford]

What exactly does "go south" in the pump? Are there seals that take a crap? Some kind of impeller?



It just doesn't make sense for the truck to run like crap one minute and then run like a champ the next. It seems to me to be some kind of electrical problem , i. e. , sensor kicking bad data to the ECU.



But like I said, I'm diesel stupid, and I'm just guessing ...



Thanks for the input

Stu Mumford

 

[WTBurke]

Stu... First get the quickie little fuel pressure Gage with the 18" rubber line (from Geno's) and fitting to place onto your Schroeder valve at the VP-44 fuel input port. Check your fuel pressure at idle as delivered from your lift pump. You must be at 15 psi and at a good rev up you should not drop below 12 psi. These are nominal figures but, good goal levels.

The point of this is to verify the LP has or does provide adequate fuel quench to the VP-44 at all times. Keep in mind that a great portion of fuel is circulated through the VP and returned to the tank for "cooling" purposes. If your LP has become weak the lack of flow has most likely "starved" your VP-44 and it's now been internally injured. These VP-44's are building pressures near 18000 psi to inject the Cummins cylinders... thats big grunt. The lack of a constant flow of "clean" diesel fuel causes these VP's to fail in short time.

Monitoring fuel pressure delivery to the VP-44 is required at all times during operation. It will save you grief.



William

 

[s2Mumford]

William, my engine started kicking error codes over a month ago with no perceptible difference in performance. I read up on what the codes meant and suspected my LP was failing, I replaced it with a FASS system.

The first time it went into limp mode was 2 weeks after the FASS install.

I'm going to go rattle around all the wires this morning and see if any are loose or have bad connections.

Thanks for your input, got any other ideas?



Stu Mumford

Riverside CA

 

[WTBurke]

Sorry Stu

Your signature lacks the details for me to see what is already done on your truck. I will say I replaced my LP only after it had gone soft and I don't know how long it had been that way because I made the big mistake of not monitoring fuel pressure to begin with

Afterward even with an adequate psi/volume flow with a new LP the VP had already been nurfed. The gradual performance drop off is subtle and I've seen many guys report that after the VP was replaced the zip and giddy-up was back to normal and fuel mileage had returned to pre-problem levels.



I believe my horse has been slow in the giddy-up department only by "seat-o-the pants" judgment. Also fuel mileage has not been where it used to be (not winter fuel) but, overall this was also subtle.



BTW... when I had the "dead-peddle" syndrome occur I would back off the throttle all the way and then depress to the normal position at that speed and the rig would then respond in a normal fashion.



I know I had been in several pi$$ing contests on Interstate 5 at speeds exceeding 100 mph at the time when my LP was soft and I would assume the VP-44 went into "sucking fuel for life" mode and perhaps this was when it took on self damage. I'm sure the psi at the time was in negative numbers.



Bottom line as I've learned here on TDR... . if you have the 0216 code... . it's "lights-out" for the VP in short time.



William

 

[s2Mumford]

I hear ya!



I'm sorry, I thought I put all that stuff in my sig, I'll re-edit it right now.



The thing that I am having a hard time with is choking doown the cost of a new VP when mine is still kicking ass. I just pulled a ~6500lb package back and forth across teh Mojave Desert, up and over Chiriaco Summit, truck ran sweet on the way there, went boating, driving around town without the trailer went into limp mode, fixed itself, ran great all the way home. Averaged 14. 4 mpg, pulled strong.



I looked under the hood before I left for work, jiggled all the wires, and I think I may have sussed it.



The new harness that powers the FASS pump was sitting right on the starter.

I'm wondering if that was causing a short...



I'm going to keep hammering away until I'm left by the side of the road. Until then, I'm going to keep a rabbit's foor on my keychain and a six pack of sodas on ice in the bed



Thanks

Stu Mumford

 

[rholcom2]

Buying a Code Reader

If I were to buy a ODBII code reader on Ebay like http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2480281816&category=43989 , would it work for my 98. 5 2500?? Or would I have to buy a more elaborate one?? Do we have the generic plug in?? Or do we have to buy a specialized adapter? 36 bucks doesnt seem too bad for a code reader. Thanks!!!!

 

[s2Mumford]

Start a new topic called "OBDII Code reader question" rather than hijack this thread, please.



Thanks

Stu Mumford

 

[Henry]

Read my post-Low Map Sensor Volts

Exact same problem I am having. Computer and consensus is that the Map Sensor is failing. Truck drives fine and then accelerates sluggishly. Comes and goes, yadda yadda yadda. :{

 

[WTBurke]

Henry



Are you seeing codes 236 237 238... . ? this thread is about 0216 injection pump timing failure. I did not start this thread but, focus is important.



William

 

[s2Mumford]

Thread is about "Limp" mode... .



If anything can cause it, I'm all ears.



As long as I have a roadmap to troubleshoot from, I'm happy.



Thanks

Stu Mumford