Surging issues now with codes

[Foehammer]

Problem: Explain your problem in concise language---- My truck runs fine at normal speed but occasionally when it is warmed up to operating temp and i have to stop at a light, after i take my foot off the accelerator and after i place my foot on the brake and the rpm's drop down to about 600(idle speed) it will surge quicklly 2 or 3 quick little "vrooms"(rpm 800-900) Throws no codes initially ( see lower down)
Demographics: tell us about your truck and your ambient conditions:Las Cruces NM 89* temp in after noon
- Year: 1994
- Truck model and class (ie: c2500) K1500
- Automatic or Standard Automatic
- Mileage: (indicate miles or km) 186000 mls
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc)D-Tech PMD bumper mounted on heatsink,CDR
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? "S" engine,Turbo ,Egr(disabled)
- Ambient outside temp: (indicate *C or *F) 89* F
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) #2 diesel
- What fuel additives are you using? 8oz PS white 16 oz TC-3W oil/ fillup
- Where are you located? Las Cruces, NM

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter 4 months
- Fuel filter 4 months
- CDR Valve? 4 months
- Coolant – last flushed/replaced at dont know
- Oil – synthetic/regular, changed at regular oil leaks 1/2 qt/ week constantlly refilling
- Batteries – state of charge, (matched set) replaced at , dont know last replacement
- Battery cables and grounds (removed, cleaned and tightened): 2 months ago
- Glow Plugs - how many miles on them? dont know What type? dont know
- Injectors - last changed at dont know


History: (Describe how the problem first appeared.)
- What were you doing when it happened? slowing down to stop at stop light about 2 weeks ago
- How was the truck running fine before this problem appeared? Runs fine at normal rpms
- Has this problem ever happened before? Not more than 2 weeks ago
- Describe any related factors that might be part of the problem. Has surged in reverse about 3 times before in the past 6 months
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) Y And? prior to this week only egr codes (31,32,33) and occasional 36 but no codes when it surges Edit- I unplugged the CTS and drove around to see if surged at all with the CTS unplugged no surging which led me to think that possibly the cts was bad causing unreliable readings sent to the PCM. After driving around abit I plugged the cts back in. That was yesterday, today i checked my codes and now iIhave ( apart from the codes mentioned above) codes 15-engine coolant temp sensor circuit-high input,42-fuel temp sensor circuit-low input,57-5 volt reference low,62-Turbo boost sensor cicuit low input,84-Acc. pedal position sensor system,99-Acc. pedal position sensor(B)circuit

Diagnostics:

1] Starting:
1a] Does the engine start? Y
1b] Does the engine crank over? Y
1c] Are your batteries fully charged? Y
1d] Have you removed, cleaned, and tightened all battery connections? Yes 2 months ago
1e] Does your Wait to Start light come on for a time? no wait to start glow plug light only
1f] Does your glow plug light come on? Y For how long? 10 secs
1g] Do you see smoke from the exhaust while cranking? Y when coldWhat color? whitish

2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? Y
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? Y
2c] Loosen the inlet line from the IP – is fuel coming out (Lift Pump on)? not sure how to do
2d] Loosen an injector line and crank the engine - does fuel come out? _________
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? ___________

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) D-tech on heatsink in bumper
3b] Condition of Extension harness (if used) Vendor or Homemade? Vendor 4 months old
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. good
3d] PMD Make: Dtech
3e] PMD Age: 3 months

4] Stalling Issues
4a] Do you experience stalling only when hot? ____________
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ______
4c] Does pouring cool water over the IP seem to help with restarting? _________
4d] Is stalling momentary (engine recovers)? _________
4e] Does SES light come on when engine hiccups? _________
4f] Does cruise control quit working when engine hiccups? ___________
4g] Does re-starting seem to reset engine, restoring cruise and power? _________
4h] Changes to dash lights or instruments during stalling events? ___________

5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? no
5b] Any bubbles or oil film in coolant overflow tank? no
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? no
5d] Excessive white smoke from exhaust on cold start? dont think so
5e] Excessive black smoke from exhaust under hard acceleration? a little black smoke when i move from stopped, more black smoke when i punch it

6] Performance Issues
6a] Do you have gauges? no
6b] Maximum boost under load? dont know
6c] Have you added a performance PCM (reflash) or Chip? no
6d] Have you changed exhaust / downpipe / crossover? no

6e] Wastegate – mechanical or vacuum? vacuum

7] Temperature-related Issues:
7a] Single or dual thermostats? single
7b] Have you replaced them lately? Manufacturer of replacements? no

7c] Have you pulled and cleaned Radiator and coolers lately? no

7d] Have you replaced the fan clutch? Manufacturer of replacement? no

7e] (winter) Have you tested your antifreeze? Good to what temp? __________
7f] (winter) Are you using a winter grille cover? ___________

I'm suspicious of my Optical sensor filter harness I took it off to see if code 36 was caused by harness and shortlly after ( within 5 days) it started surging, today i put it back on to see if surging stopped but it still surged and runs rougher
Edit- I unplugged the CTS and drove around to see if surged at all with the CTS unplugged no surging which led me to think that possibly the cts was bad causing unreliable readings sent to the PCM. After driving around abit i plugged the cts back in. That was yesterday(6-17-09), today i checked my codes and now i have ( apart from the codes mentioned above) codes:
15-engine coolant temp sensor circuit-high input,
42-fuel temp sensor circuit-low input,
57-5 volt reference low,
62-Turbo boost sensor cicuit low input,
84-Acc. pedal position sensor system,
99-Acc. pedal position sensor(B)circuit
__________________

 

[gmctd]

That's usually the first sign that the FSD has begun failing - however, that 5v Ref error sorta indicates a wiring\connector problem when combined with the fuel, Boost, and APP errors, as the APP (and other sensors) uses the 5v Ref for signal source - check your wiring, connectors and grounds, first - the CTS errors you, of course, created

 

[buddy]

Could be coincidence codes, caused by some new issue.

The 800rpm revs makes it CTS likely, but does that just mean its been idling at 800RPM with the CTS harness unplugged? try instead jumpering the harness with a 300 ohm resistor so it thinks its 180*, so it will idle and advance like normal when warmed and see if the surging is still there.

 

[JMJNet]

Also check all your grounds.

 

[Foehammer]

ok after having plugged the CTS back in and clearing the codes then driving around for a few days all the new codes havent shown back up i think they were caused by my driving around with the CTS unplugged at least that is what im hoping