F150 Surging at Constant Speed

[fordgirl]

Affirm. Truck runs the same with both tanks and both tanks have the same pressure. Fuel pressure regulator? Anyway to test it before I replace another part??

 

[O'Rattlecan]

If you can check fuel pressure before and after the regulator, that's the only way to check it. I have no experience checking it before the regulator, but that's how it would be done.

Hopefully someone else jumps in with that experience.

Luckily, it's not a terribly expensive part.

Ryan

 

[dustybumpers]

To test FPR, hook gauge to port, start truck, remove vacuum line to fpr. Guage should rise 5 pounds. If not FPR is bad. Most times when the fpr goes bad, it wipes the check valves out on the fuel pumps, allowing the pump to pump return fuel into the wrong tank.

 

[dustybumpers]

I'm betting more on a transmission shudder/ torque converter lock up issue than a fuel problem.
try pulling the codes again

 

[fordgirl]

I did check the rise in psi when I disconnected the vacuum line from FPR and it was within spec.

I also think I should be getting some code relating to tranny or cylinders misfiring. The only code I have is 211 for PIP sensor. It is a CM code on KOEO. CEL only flashes 3 times on start up when it has an initial erratic idle.

I feel like there is something seriously wron with my truck and I am confused on why I am not getting more codes.

I will be testing the EGR valve today.

Thanks for the help!

 

[dustybumpers]

Transmission will not show mechanical codes, only electrical codes. If you have a pressure, or converter shudder problem, it will not show up as a code

 

[Artistpro]

I wonder if my problem is similar to your post. 1989 F250 351W 2wd
Motor races upon start...sometimes rpm suddenly drops back to normal after a few minutes driving. A mechanic told me once that he cleaned the throttle body...which cured things for a while. I'd try that again myself if I shouldn't be looking somewhere else. Any clues? I'm a moderate when it comes to fixing my truck...with a bit of help from FTFs Iv'e had success many times. Your thoughts appreciated.

 

[fordgirl]

So I also have that problem...(from earlier post)...When I start my truck (hot or cold) about 90% of the time within 1 minute of being on, the engine will rev up to 1500rpms with the CEL flashing 4 times, then almost stall and settle down at around 800rpms. I have also noticed that if I give it gas when it is revving, it will start to stall. I have cleaned the throttle body and it didn't help. Here is the thing...When I was getting this idle issue (along with voltage issues), the only code I was getting was for PIP circuit fault (211). I replaced the battery cables and terminals. Then the idle problem is pretty much non existent now, but now I am getting a PIP curcuit FAILURE code. I am pretty sure the motor racing on start up has to do with the PIP circuit. However, I am on my third distributor, so it is not the PIP itself, must be wiring somewhere down the line.

SYMPTOMS: Truck runs sluggish, about 1/15 starts will ramp up RPMs on start-up, getting a PIP circuit failure, smells like fuel.

Let me know if you find anything out! From what I know, this start up is a common problem with Fords around these years.

 

[Artistpro]

What's the chances my problem isn't quite so deep? I've looked the area over for disconnected or broken vacuum lines...took the airflow hoses from teh filter and throttle.
Seems odd that my problem could be fix'd by replacing the battery cables & terminals, but I'd try anything to avoid exploratory mechanical $urgery. My lame intuition is that something is stopped-up...by the way I'll drive off with high rpms and then it 'coughs' and instantly breaths normal. Now it quit coughing and settling down...starts high and ends high...just wonderful :-( If there's something FTFs can think of I should try, please lemme know.

 

[dustybumpers]

I think pull the IAC off and clean it. Could be a carbon build up.

 

[blacksnapon]

You Have to fix your PIP code

NA1 CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) 211: ERRATIC IGNITION
DTC 211 indicates two successive erratic Profile Ignition Pickup (PIP) pulses occurred, resulting in a possible engine miss or stall.

Possible causes:

Loose wires/connectors.
Arcing secondary ignition components (coil, cap, rotor, wires, plugs, etc.).
On-board transmitter (2-way radio).*
Verify all radio and condenser installations. Carefully follow manufacturer's installation instructions regarding the routing of antenna and power leads.
Are any of the above present?
Yes No
SERVICE as necessary. CLEAR Continuous Memory (REFER to Quick Test Appendix, Section 5A .) RERUN Quick Test. For No Starts on 2.0L Probe:
GO to AA1 .
All other No Starts:
REFER to Section 8A for DI Diagnostics.
All others:
GO to NA2 .

NA2 CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) 212
DTC 212 indicates a loss of IDM input to the PCM.

Possible Causes:

Open harness circuit.
Shorted harness circuit.
Damaged Ignition Control Module (ICM).
Damaged Powertrain Control Module (PCM).
Is vehicle a No Start?
Yes No
REFER to Section 8A for DI Diagnostics (2.0L Probe, Section 8B). GO to NA3 .

NA3 CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) 212: CHECK IDM CIRCUIT CONTINUITY
Key off.
Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Disconnect Ignition Control Module (ICM).
Measure resistance between Test Pin 4 at the breakout box and IDM circuit at the ICM vehicle harness connector.
Is resistance less than 5.0 ohms?
Yes No
GO to NA5 . SERVICE open circuit. REMOVE breakout box. RECONNECT PCM. CLEAR Continuous Memory. RECONNECT all components. RERUN Quick Test.

NA5 CHECK IDM CIRCUIT FOR SHORTS TO POWER (EXCLUDING VREF)
Key off.
Breakout box installed.
PCM and ICM disconnected.
Measure voltage between Test Pin 4 at the breakout box and battery negative post.
Key on, engine off.
Measure voltage between Test Pin 4 and Test Pins 40 and 60 at the breakout box.
Is any voltage reading greater than 10.5 volts?
Yes No
SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RERUN Quick Test. GO to NA6 .

NA6 CHECK IDM CIRCUIT FOR SHORTS TO VREF AND PIP
Key off.
Breakout box installed, PCM disconnected.
ICM disconnected.
Ignition coil disconnected on Non-CCD vehicles (refer to Pinpoint Test Schematic ).
Disconnect Scan Tool from Data Link Connector (if applicable).
Note: For proper results of this test, the Scan Tool must be disconnected. Due to the circuitry of the Scan Tool and the vehicle, voltage can be fed to the VREF circuit giving a false indication of a short to power.

For Shorts To VREF:
Measure resistance between Test Pin 4 and Test Pin 26 at the breakout box.
For Shorts To PIP circuit:
Measure resistance between Test Pin 4 and Test Pin 56 at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
GO to NA7 . SERVICE short circuits. REMOVE breakout box. RECONNECT all components and SCAN Tool (if applicable). RERUN Quick Test.

NA7 CHECK IDM CIRCUIT FOR SHORT TO GROUND
Note: During this check when 4-wire HO2S is connected to the vehicle harness on DI vehicles, a short to SIG RTN (Pin 46) may be indicated in conjunction with an actual PWR GND short.

Key off.
Breakout box installed, PCM disconnected.
ICM disconnected.
Scan tool disconnected from Data Link connector.
Ignition coil disconnected on Non-CCD vehicles (refer to Pinpoint Test Schematic ).
Measure resistance between Test Pin 4 and Test Pins 20, 40, 46 and 60 at the breakout box.
Is each resistance above 10,000 ohms?
Yes No
RECONNECT Scan Tool. GO to NA8 . REMOVE breakout box. SERVICE short to ground in IDM circuit. RECONNECT all components. CLEAR Continuous Memory. RERUN Quick Test.

NA8 CHECK ICM
Key off.
Breakout box installed.
Connect PCM to breakout box.
Reconnect ignition coil and ICM.
Connect DVOM between Test Pin 4 and Test Pin 16 at the breakout box.
Start engine.
Observe DVOM when voltage is allowed to stabilize.
Lightly tap on ICM to simulate road shock.
Wiggle ICM connector (for 3.8L AX4S, 3.8L RWD, 3.0L, 7.0L and 7.5L Trucks, wiggle ICM, GCM and CMP sensor connectors).
A sudden change in voltage indicates a fault.
Is a fault indicated?
Yes No
DISCONNECT and INSPECT connectors. If connector and terminals are good, REMOVE breakout box, RECONNECT all components and REFER to Section 8A , DI Diagnostics (2.0L Probe, Section 8B). GO to NA9 .

NA9 CHECK EEC HARNESS
DVOM still connected between Test Pin 4 and Test Pin 16 at the breakout box.
Key on, engine running.
While observing a voltage change as in NA8 , perform the following:
Grasp vehicle harness closest to ICM connector (for 3.8L AX4S, 3.8L RWD, 3.0L, 7.0L and 7.5L trucks, wiggle ICM, GCM and CMP sensor connectors). Shake and bend a small section of the EEC harness while working toward the dash panel. Also wiggle, shake and bend the EEC harness from dash panel to PCM.
Is a fault indicated?
Yes No
ISOLATE fault and SERVICE as necessary. REMOVE breakout box. RECONNECT all components. CLEAR Continuous Memory. RERUN Quick Test. GO to NA10 .

NA10 CHECK PCM AND HARNESS CONNECTORS
Key off.
Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc.
Are connectors and terminals OK?
Yes No
GO to NA11 . SERVICE as necessary. REMOVE breakout box. RECONNECT all components. CLEAR Continuous Memory. (REFER to Quick Test Appendix, Section 5A .) RERUN Quick Test.

NA11 CHECK PCM FOR SHORT TO POWER
Key off.
Breakout box installed.
PCM connected to breakout box.
For vehicles with Remote Mounted ICM and Camshaft Position (CMP) sensor:
Disconnect ICM and CMP.
7.0L Truck:
Also disconnect Governor Control Module (GCM).
All others:
Disconnect ICM.
Measure voltage between Test Pin 4 and chassis ground.
Key on, engine off.
Measure voltage between Test Pin 4 and Test Pins 40 and 60 at the breakout box.
Is any voltage reading greater than 10.5 volts?
Yes No
REPLACE PCM. REMOVE breakout box. RECONNECT all components. RERUN Quick Test. GO to NA12 .

NA12 CHECK PCM FOR SHORT TO GROUND
Key off.
Breakout box installed.
PCM connected to breakout box.
Ignition coil (Non-CCD only), ICM and CMP sensor disconnected.
Measure resistance between Test Pin 4 and Test Pins 40, 46 and 60 at breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
REMOVE breakout box. RECONNECT all components. For further diagnosis, REFER to Section 8A , DI Diagnostics (Probe, Section 8B). REPLACE PCM. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.




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[Artistpro]

Thanks for the suggestion. I pulled the IAC (still fairly new) and sprayed it with choke cleaner...it didn't seem sticky or dirty. Motor still revs up...and sometimes (but rarely) drops back down to normal 'on it's own'. Re-starting makes the motor rev again.
I try to give my truck whatever it needs...wish it would just tell me what.
I wonder if the parts house has a read-out device for my '89. Yeah, that's the ticket! I'll just interpret some blinking lights.

 

[Artistpro]

too high idle

I used to be better weaving my way around a simple forum...but don't see my 'quick reply'...I guess a 'Post Reply ' is where i need to be. Anyway, thanks for your suggestion...I tried choke cleaner all inside the Idle control Valve...didn't seem sticky..plunger moved...heck, it's practically still new. No improvement...still idling too high. I'll see if the parts house guys have a reader for my computer (1989)? I still invite your suggestions.

 

[Artistpro]

Idling too fast

Without much hope, I swapped the (less than a year old) idle control valve with one of two other older ones I had. The truck is running fine now. I told the crew at Auto Zone, "There's some crap-for-parts being sold to us in America' Two of them bust out laughing. I've no promise that what I did will keep things fix'd because the older ICV was thought to have failed...yet is doing it's job again. I'm not going to argue with success however temporary. Thanks for the responses from FTF. I really need advice and appreciate you.

 

[fordgirl]

Nice! In the mean time I changed out my cap and rotor (showed signs of corrosion and loss of spring tension) with no improvements. I guess I will try to clean/swap the ICV since that worked for you.

 

[fordgirl]

I wish my problem was that simple...first step to test IAC failed. KOEO, I got 0.015V at the electrical terminals that connect to IAC. Haynes manual says I should get 10.5V. So the IAC is not even getting powered, so my guess, the pintle is stuck where it last was when it was actually powered.

I started a new thread to solve PCM to IAC no signal problem. No responses yet.