Engine/Transmission (1998.5 - 2002) Hard Start / Long Start / Slow Start

[SScandalis]

Update on this problem

This Hard Start / Long Start / Slow Start problem seems to be directly related to engine temperature and engine sitting time before the next restart after the engine water has come up to temperature and the engine compartment has heated up. The application of the TSB 18-015-00 ECM reprogramming a month ago has essentially done little to help.


Question

Does anyone have experience with the "Defective Fuel Line Check Value" (and Crankshaft Position Sensor) for long engine crank cycles described in TDR Issue 62, page 25 and TDR Issue 64, page 28?

My Camshaft Position Sensor (CMP) was replaced at the same time as the in-tank fuel pump was put in 13 months ago. Apparently the Camshaft Position Sensor doesn't effect the injector pump, though many have said the Crankshaft Position Sensor (CKP) does. The only engine code that read out a month ago was for the P0122 APP Sensor (accelerator petal position sensor), which seems to be a phantom code that sometimes comes on when the engine takes too long to start.


Observations in the last month

The application of the TSB 18-015-00 ECM reprogramming has essentially done little to help with this Hard Start / Long Start / Slow Start problem.

Since the Dodge dealer's technician reprogrammed the ECM one month ago the start times continue to vary greatly, ranging from 0. 92 sec to 6. 02 seconds as measured with a stopwatch.

Short start times of 1 to 3 seconds most often occur when engine is ambient temperature in the morning or has sat for just a few minutes (1-5 minutes) when the engine is up to temperature (180-190 deg F) before restarting, or when the engine has sat for 2+ hours before restarting.

Long start times of 3+ seconds most often occur when the engine has been warmed to full temperature and then sits 20 to 60 minutes before the next restart.

Restart times between 5 to 20 minutes when engine is warm vary, some are faster and some are slower.

Sometimes the Check Engine Light will come on after one of the long starts, but not always. Engine Light resets itself after 5 restarts after being set on. I haven't had the engine code read yet in the last month, but earlier the technician only found the Accelerator Petal Position Sensor code.

The symptom is as if shutting down the engine for 20-60 minutes after being up to temperature is placing something mechanical or electronic in a critical temperature zone that leads to the long start times.

Even when the engine / engine compartment cools down the start times are still much longer than the approximately 0. 5 sec instantaneous starts this truck had for over 10 years until just a couple of months ago. As mentioned earlier, during cranking the engine acts like it is dead cranking, no fuel getting to the cylinders until the moment it finally starts.


Example start times with engine and air temperature and sitting time before restart

Date -- Start Time (sec) -- Engine/Air Temp -- Sitting Time -- Check Engine Light
6/10 1. 48 cold / 65 Overnight
6/10 1. 50 cold / 70 10 hr
6/10 1. 37 160 / 70 11 min
6/10 3. 25 150 / 65 53 min Check light came ON
6/10 2. 60 180 / 60 2 min "
-----
6/11 1. 45 cold / 65 13 hr "
6/11 1. 37 180 / 65 3 min "
6/11 1. 41 cold / 60 10 hr "
6/11 1. 00 170 / 60 2 min OFF
-----
6/14 1. 27 cold / 75 46 hours
6/14 1. 01 170 / 75 5 min
6/14 0. 96 150 / 75 45 min
6/14 1. 32 170 / 75 1 min
6/14 4. 86 160 / 70 40 min Check light came ON
6/14 2. 26 170 / 70 3 min "
6/14 3. 15 170 / 70 2 min "
6/14 0. 97 180 / 70 3 min "
6/14 2. 35 170 / 65 2 min "
6/14 2. 20 160 / 65 3 min OFF
-----
6/15 1. 03 cold / 75 17 hr
6/15 0. 97 cold / 60 8 hr
-----
6/16 0. 94 cold / 75 12 hr
6/16 1. 26 180 / 75 1 min
6/16 0. 93 cold / 80 9 hr
6/16 3. 48 160 / 75 20 min
6/16 2. 28 140 / 65 90 min
-----
7/2 0. 99 cold / 75 14 hr
7/2 5. 32 170 / 75 15 min after freeway w/heavy trailer
7/2 1. 23 140 / 75 2 hr
7/2 3. 29 170 / 75 30 min
7/2 2. 37 140 / 70 3 hr
7/2 2. 32 140 / 65 2 hr
-----
7/3 0. 98 cold / 65 11 hr
7/3 5. 10 180 / 70 10 min
7/3 6. 02 180 / 70 10 min

 

[Ron Bissett]

if you have a AIC did you clean or replace it . It could be the windings on the starter when hot will not start cools down will start. Bad ground start some times caused by location on block rust,dust,oil ,etc or the cable to starter ,battery , calmps on battery or post, water in fuel, dirty filter, ditry air filter, bad air intake sensor or bad wire to sensor or fouled by soot and oil ,Also all the other suggestions of others ,If all else fails read the instructions found in the repair manual for your year truck. Ron

 

[SScandalis]

Ron,

I'm not sure what an AIC is, can you elaborate?

As for my starter it seems to turn over the engine the same whether the engine is cold or hot. Also, I replaced the starter contacts with the 24 volt contacts several years ago so no more sticking contacts.

Starter and battery cables have been checked. Two new batteries in last 2 months, new air filter too. The truck runs great once started, it's just the initial start time that's too long.

I've measured battery voltage during starting and have about 12. 5 volts before turning over the engine and capture 10. 5 volts as the lowest drop during cranking & starting.

Dealer technician checked lots of things a month ago. I'll ask about the air intake sensor as well as the crankcase position sensor when I take the truck back again because the last repair (ECM reprogramming) doesn't seem to have helped.

 

[SScandalis]

Any opinions / experiences regarding a new recommendation below to change the STARTER to fix this issue?

The Dodge technician took another look to see if this Hard Start / Long Start / Slow Start issue is either 1) Crankshaft Position Sensor mounted near the starter or 2) the Overflow Valve (check valve) located on the fuel return line of the VP44 injector pump.

Here's a nice discussion of the Overflow Valve symptoms and diagnosis: Overflow Valve

After new investigation the technician doesn't think the issue is either the Crankshaft Position Sensor or the Overflow Valve, but instead is recommending a STARTER replacement.

Reasoning is that the starter seems to turning slower than it should, therefore cranking the engine slower and not building up pressure fast enough for a fast start. When the engine is hot he thinks the starter must be turning even slower, therefore results in even longer start times.

The current behavior has been:
1) 1 to 3 second starts if the engine is cold or has sat for less than 10 minutes or longer than 2 hours after coming up to full temperature and engine compartment warm up.

2) 3 to 6 second starts after engine is up to temperature if it has sat for at least 20 minutes but less than 2 hours.

Earlier behavior for 10+ years until 3 months ago was:
Near instantaneous starting of around 0. 5 seconds almost always after turning the key.

 

[SScandalis]

Question: Does anyone know a way to easily "measure" cranking speed / cranking RPM?

Summary of latest diagnostic/fix progress and list of suspects

I have my truck back now. After talking with the service advisor and seeing technician notes this morning I think I'm going to wait for a couple of weeks and listen to the starter spin speed during shorter starts (1-3 seconds) and long starts (3-6 seconds) and, if I can, try to find another similar year truck with 24-valve Cummins that starts even faster (0. 5 sec like mine used to) to listen to its relative cranking speed too.

If I hear a distinct slower crank speed when hot that might add evidence to indicate that I should replace the starter.

FYI: Larry B's Foster Truck LarryB's Dodge starting problems solved here. has the new Nippon Denso OEM Starters that come with SuperSize contacts installed in case the starter gets replaced.

In spite of the mechanic's latest diagnosis to replace the starter (~$1,000 part/labor quoted at Dodge dealer) and mechanic's determination that the problem is not because of #1 and #2 below, I think there continues to be at least 3, maybe 4, suspects for this hard start / slow start issue that started happening three months ago, based on the experiences of others on discussion forums such as Turbo Diesel Registry (TDR) and studying the Dodge service manual.

Unfortunately trying some of the suspects below are more costly / time consuming than others but none is pointed to directly with enough clarity right now through hard diagnostic results.

Suspects in order of estimated cost/time to try to effect a fix

1) Overflow Valve (check valve) at injector pump fuel return line could be sticking open (normally should open at 14 PSI) which would allow low level pressure to bleed out of injector and/or might be staying open during restart and causing initial pressure buildup to take longer during the cranking time (a time when the engine turns much slower than when running).
- 1998 Dodge Ram "Service Manual Supplement BR/BE" has an interesting caution on page 14-31 emphasizing the importance of the Overflow Valve: "FUEL INJECTOR PUMP New or remanufactured fuel injector pumps should have a new overflow value temporarily installed into side of pump. Do not install a used overflow valve into a new or remanufactured injection pump.
- One user reported "lightly tapping" on the check valve to get his truck to start.
- Discussion of the Overflow Valve symptoms and diagnosis: Overflow Valve.

2) Crankstaft Position Sensor (CKP) sensor or wiring/connector not turning on the Engine Control Module and VP44 injector pump to deliver fuel during initial engine cranking.
- Haven't found a good diagnostic method yet.

3) Starter spin speed when hot and sitting for 20 minutes to 2 hours may not be revving the engine/injector pump fast enough to build up fuel pressure for a quick start.
- Sounds possible, but engine is also dry cranking - i. e. no sputtering, as if there is no fuel at all. Injectors into cylinders have a "pop-off" pressure of about 4,500 PSI per 1998 BR/BE Service Manual Supplement before they will open so maybe that's why there is dry cranking.
- If there is a way to attach a tachometer-like device that can count very low RPMs on the engine/starter during cranking that would be real helpful. That might help provide a definitive diagnostics for a hard start / slow start problem to help determine whether to install a new starter when the starter isn't experiencing any other classic starter wear or failure symptoms.

4) VP44 injector pump failing again (internal electronics board failing, internal mechanical issue?)
- No external codes or driveability issues are happening after the hard start / long start.
- Most costly and time consuming to try. Need much more data pointing to a failure to consider this at all.
- This is an excerpt from Blue Chip Diesel Performance Specialists


Earlier Repairs
1) Replaced stock 12 volt starter motor contacts with 24 volt SuperSize contacts several years ago when stock 12 volt starter contacts were sticking/welding. No starter problems or sticking at all since this upgrade.

2) VP44 high pressure pump and engine-mounted lift pump were replaced 3-4 years ago. Lift pump was providing <5 psi pressure per Diesel Technical and took out the expensive VP44 high pressure pump.

3) Engine mounted Lift Pump was leaking fuel through the electrical connector and was replaced with the in-tank fuel pump at Dodge a year ago.

4) CAM Position Sensor was replaced a year ago too.


Already Tried Recently
1) Two new batteries, new air filter, drained fuel out of filter to make sure no water was in the fuel, several full tanks of fuel.

2) TSB 18-015-00 "Driveability enhancements for winter fuel use and for hard starts" was applied a month ago.
- The application of the TSB 18-015-00 ECM reprogramming has essentially done little, if anything, to help with this Hard Start / Long Start / Slow Start problem.

 

[JLandry]

Question: Does anyone know a way to easily "measure" cranking speed / cranking RPM?

Yes...



You could use a photo tachometer like one of these aimed at the harmonic balancer while cranking:



Photo Sensor Tachometer



Digital Photo Sensor Tachometer



The photo electric eye must be within about 2" to 10" of the object being measured and it needs a shiny spot passing by in order to trigger the rpm counter. A piece of silver reflective tape available from auto parts stores works great for this. It would likely take two people to take the measurement... one laying under the truck taking the reading from the crank and the other operating the starter switch... or possibly just one person laying under the truck if you have a remote starter switch to activate the starter solenoid.



Unfortunately this sure sounds like a classic VP44 computer heat-soak related problem. I know you don't want it to be and you've done a good job ruling out other obvious things. Once you satisfy yourself there's nothing wrong with the starter, then it looks like there's nothing else left but to try another VP44.



Good luck,



John L.

 

[Ron Bissett]

slow statr no start

By now you have checked every thing Except the Air intake sensor Located on the side of the block near the lift pump looks like a spark plug except it has a ball in a plastic cage at the tip Soot ,oil dirt ,can and will clog it and it will cause the control module to get the wrong temp reading to change the air fuel charge to eng. Ron . #@$%!Oo.

 

[JKreiss]

Does it(air intake sensor) look like it actually goes into the block, i can't find anything in the book? How did you clean yours? I'm trying to rule out every possible thing before i have to think about replacing another injection pump in only 10k mi. Also, where can i find an overflow valve/ check valve?

 

[Fhawk]

Slow Starting

I have a 1999 , 149,000 miles, ans starting was slow. History shows 80,000 I changed contacts with a set of Larry Buck and worked until now. I found that the fuel filter canister had been leaking and fuel ending up on the starter. Bought a new starter from LARRY BUCK and all is well... Thank you Larry. I will rebuild my old one and have a replacement for the future.

Also kudos to the TDR website. What a lifesaver.



Frank:-laf

 

[POBRO]

I was having close to the same problem, after a no start problem, had new batterys, fuel filter,& air filter. Would be very slow to start cold & somtimes not start at all when hot , most of time could put jump box on & would go ahead & start when hot. I did not think was starter as starter was replaced less than a year ago, two days ago, after 8 hrs trip, truck was turned off for 1 hr , & then try to restart ( with jump box ) starter went dead ( not even a click ) - chnged out starter with new one - truck starts like it did when new !!!!!!!!