15 replies to this topic

[Jarnold9223]

Hello all
This is my first post here and sadly I have a deadline fast approaching for this project so any help would be greatly appreciated.

I bought an RV in January to restore for the upcoming Indy 500. When I bought it, it ran great. On my way home though, it started sputtering and would no longer run. Had to tow it home. . . Since then it's gone through an overhaul. On the motor I have replaced plugs, wires, distributor, PCM, cleaned throttle body, dropped and cleaned tank, new fuel pump, blew out fuel lines, new o rings on injectors, and fuel filter. I don't think I'm forgetting anything but I will update as I recall.

When starting it generally won't have a problem. Once it starts it'll idle forever, just rough. Throttle response is most of the time laggy and seems unresponsive. It is smoking quite a bit but would expect after it sat for 3+ years. Also the smoke doesn't smell like oil. Smells pretty normal.
The only other symptom that I have is that whenever it's running and I unplug the MAP sensor it idles absolutely wonderfully. Can rev up and no problems whatsoever except that when you drop into drive it'll die.

Sorry for the lengthy post but I figured I would be thorough. Absolutely any help would be greatly appreciated.
Thanks in advance!

[miesk5]

Yo Jarnold9223,

Welcome!

Check for vacuum at the MAP sensor vacuum line, you will either have very low vacuum or no vacuum at all. The plastic lines like to break, thus causing this condition. See my vacuum leak below.

 

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.co...7&mode=threaded
Some basics;
The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test

and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around or Idle to heat the engine up; and shift thru all gears including Reverse if possible.
Make sure A/C is off and transmission is in Park (automatic); or in Neutral for a Manual & release clutch.
Then turn off engine, all accessories/lights (close driver's door) , etc.

Do KOEO test First
Post Code(s) here according to:
KOEO
&
KOER

...

 

See  my vacuum leak test in post #20 @ http://broncozone.co...de-44/?p=125535

It would be good to grab a vacuum gauge as you will see.

..

Anything that interferes with the MAP sensor's ability to monitor the pressure differential may upset the fuel mixture and ignition timing. This includes a problem with the MAP sensor itself, grounds or opens in the sensor wiring circuit, and/or vacuum leaks in the intake manifold (airflow sensor systems) or hose that connects the sensor to the engine.

A vacuum leak will reduce intake vacuum and cause the MAP sensor to indicate a higher than normal load on the engine. The computer will try to compensate by richening the fuel mixture and retarding timing -- which hurts fuel economy, performance and emissions.

Next, check the sensor's vacuum hose for kinks or leaks. Then use a hand-held vacuum pump to check the sensor itself for leaks. The sensor should hold vacuum. Any leakage calls for replacement.

 

Testing, Symptoms & Overview; "...a multimeter that can read frequency is normally required to check the sensor's output. But you can also use an ordinary tachometer because a tach can display a frequency signal. Here is the procedure: Connect the two jumper cables the same as before, (see diagram in site) attaching each end terminal on the sensor to its respective wire in the wiring connector. If you want to measure engine vacuum so you can correlate it to a specific frequency reading, connect a vacuum gauge to a source of manifold vacuum on the engine, or tee the gauge into the MAP sensor hose. Turn the ignition ON and note the initial reading. The reading on the tachometer should be about 454 to 464 at sea level, which corresponds to a frequency output of 152 to 155 Hz. Start the engine and check the reading again. If the MAP sensor is functioning properly, the reading should drop to about 290 to 330 on the tachometer, which corresponds to a frequency output of about 93 to 98 Hz. No change would indicate a defective sensor or leaky or plugged vacuum hose..." a vacuum gauge to a source of manifold vacuum on the engine, or tee the gauge into the MAP sensor hose. 

Source: by wellsmfgcorp

 

Orvsee http://troubleshootm...he-map-sensor-1

 ...

Here is a summary of smoke symptoms and causes:
Less $ first (less worries as well!)

Blue/Gray Smoke:
PCV System: A stuck closed PCV valve will cause excessive crankcase pressure resulting in blue/gray smoke. 
Oil burning in the combustion chamber. Pull a few spark plugs & ck iaw Spark Plug Diagnostic Chart 
http://www.gsparkplu....ult-diagnosis/
Oil Deposits Symptoms: Oily coating caused by poor oil control. Oil is leaking past worn valve guides or piston rings into the combustion chamber. Causes hard starting and misfiring.
Valve Seals: Leaking valve seals will cause blue/gray smoke at startup because oil leaks past the seals into the cylinder after the engine shut down.

Valve Guides: Excessive clearance between the valve stem and the valve guide allows oil to leak past the gap into the cylinder.

Piston Rings: Worn or damaged piston rings will cause blow-by resulting in blue/gray smoke.

Worn Cylinder Walls: Worn cylinder walls cause blow-by resulting in blue/gray smoke. 
--

Black Smoke: Black exhaust smoke is an indication of rich fuel condition. These are possible causes:
Fuel Injectors: A leaking or dripping fuel injector will cause a rich fuel condition.
Fuel Pressure Regulator: A stuck closed fuel pressure regulator will cause a rich fuel condition. Pull a plug or more and inspect.
Fuel Return: A restricted fuel return line will cause a rich fuel condition. 
--
White/Gray Smoke: White exhaust smoke is an indication that coolant is burning in the combustion chamber. These are possible causes:
Cylinder Head: A crack in the cylinder head (around the coolant jacket) will cause coolant to enter the combustion chamber. 
Engine Block: A crack in the deck of an engine block near the coolant jacket will cause coolant to enter the combustion chamber. 
Head Gasket: A damaged or blown head gasket will cause coolant to enter the combustion chamber resulting in white/gray smoke coming from the tailpipe."
by ASE Study Guide

GL!

Al

[Jarnold9223]

Thanks a ton Miesk5. I'll be working on it again this afternoon and I will certainly follow your advice. I'll post results in a bit.

[miesk5]

Yo,

YW!

Ok, will be around.

[miesk5]

Yo,

Although I am signed in 24/7, I may not be here.  Will check here every hour or so until 7 PM EDST.  

Then in morning again.

[Jarnold9223]

Just got back home with a new MAP sensor and got the ECM rebuilt after having it tested. The mechanic said he was surprised it ran at all. About to throw these on and see what happens. Thanks for the info

[miesk5]

Yo,

Ok, GL!

 Will be back in morning and through the day periodically until you have it running well.

[Jarnold9223]

Tested it a little bit ago and no luck. Ecm and map sensor are both things I dont mind paying the money I did to know that they're perfect.

I can rev it up into the higher rpms (no tach) and the engine sounds great but once it gets down to idle it will start sounding "gluggy" Sounds like it's choking. Which leads me to believe a Throttle Position Sensor could be the culprit. Or a clogged FPR potentially as well. Do you have any opinions on things I could check or what it may be. I'm checking back every so often until tomorrow when I get back to it

Thanks for the vigilance in your speedy replies. I greatly appreciate it

[miesk5]

Yo Jarnold9223,

Did you have a chance to test for codes?

 

Idle Air Control (IAC) aka IAB, etc Testby Ryan M @ http://www.fuelinjec...com/page39.html

Most significant is "bring the engine up to operating temperature. Allow the engine to idle without any driver input to the throttle or pedal. Go under the hood, and disconnect the electrical connector to the IAB. If the engine begins to stubble or stalls the IAB is functional and does not need to be repaired. If the engine idle does not change you should remove the IAB for inspection.

The IAB can pass and still need repair, or it can fail and not need replacing. The plunger and internal spring can get clogged with dirt and oil. This will slow down the air flow and not allow the IAB to function properly. Remove the IAB and clean it. There are 2 halves to the IAB, and you can not buy just one half, but you can take it apart to clean it. But if the internal solenoid is faulty the IAB needs to be replaced."

 

May need to clean sludge out of the passageway.

See Removal & Cleaning in a 93 5.8 

Source: by Bobby (blue)  

...

TPS Test @ http://easyautodiagn...-sensor-tests-1

..

FPR Test; "Pull the vacuum line & check for fuel...There shouldn't even be the ODOR of gas in it." miesk5 note; Check fuel pressure, install fuel pressure gauge, start and run the engine at idle. 

Pressures:

 Engine Running:  28—45 PSI, I THINK 30 psi @ idle.

 Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator.

Key ON Engine OFF: 
35—45 PSI

 

Will be back here every few hours util around 7 pm.

If you have any urgent questions over next few days, click on my name to see my profile & send me a PM.

[Jarnold9223]

Thanks Miersk.
I didn't have any luck today on it. Checked TPS and Coil. I'll run these tests tomorrow. I really appreciate the recommendations and thorough explanations.

[miesk5]

YozJ,

Ok.

Have to mow lawn, get new flag ready for Memorial Day, etc.

Will check in later and tomorrow morning.

[Jarnold9223]

Well I found atleast a big part of the problem today.

Finally went and rented an actual compression tester today. At this point I knew cylinder 1,4,&7 were all dead. Cylinder 1 is a nightmare to get to in this RV so just did the back 4. 2 for control the others to see what they're sitting at. On the good cylinders I got a reading of 120. Seems good to me. On cylinder 4 it read 90. And cylinder 7 wouldn't read anything. Decided to pop the valve covers off to see if I can see what's going on.

3 bent pushrods. . . All on the 3 cylinders that I knew were dead.

What I'm curious to is why cylinder 4 would read 90 psi and cylinder 7 wouldn't read anything?

It doesn't look like the rods damaged anything. Just kind of rattled off. Under that assumption I should just be able to replace the rods and be alright?

Thanks for your replies Miersk

[miesk5]

Yo,

Good!

As long as there is is no knocking sound I think you're ok.

 

Enjoythe weekend comingcoming, especially Memorial Day!

[Jarnold9223]

Awesome. That makes me feel a bit better about just installing new ones. I really don't want to take the head off. I'm at work right now but I'll be heading that way to install very shortly. I'll be sure to check valve movement before I put the covers back on. I'll post results (hopefully good ones) later

[Jarnold9223]

Test drive it up and down a hill near my house and everything went great after it warmed up. Ready to take it to the track on Thursday morning. Thanks for your help Miesk5

[miesk5]

Yo,

 Best news today.

Enjoy the Memorial Day Holiday.!