Hi Everyone! I'm new to the forum, and new to the Diesel world, but would like to think that I am fairly mechanically inclined. I have been working on, and researching what I assume is a MAP problem for the last several days, and haven't been able to find anything that resembles my issue on the Interwebs. I am located at about 4500' above sea level, which I think will become relevant later in the post.

This is on an early 99, to the best of my knowledge running stock tune, and no major modifications, with the exception of a freshly cleaned and oiled cold air intake, and 330K miles, 6 spd Manual.

I have a Bluetooth OBDII connector, and Torque Pro on my phone that I am using for monitoring, with the Ford PID pack installed. With the MAP sensor plugged in, the truck runs fine, but has very little power, it takes everything that the truck has to get up to speed and keep up with traffic, and there is literally nothing left. With everything connection KOEO, the Ford Specific MAP sensor reads -2.1 PSI, and the EBP sensor reads 12.7. HPOP and IPR look completely normal throughout the RPM range, based on what I have read. I added the Generic Intake Manifold Pressure, and that sensor reads at the expected 12.4 PSI. Where does this data come from? I have tried to pull barometric pressure from the OBDII also, but it always reads "No Data". With this setup, with everything connected, if I can get up to 5-7 PSI of total boost on the map guage in torque pro, WOT, 3rd gear uphill.

All of these readings line up perfectly with my elevation, based on my calculations, air pressure should be about 12.5 PSI at my elevation, except for the -2.1 PSI on the MAP sensor.

If I disconnect the MAP sensor, the truck is a whole new vehicle. I have tons of power, I can pull out into traffic, and not worry about getting up to speed. I can pull up a hill in 4th and have my RPM's go up, when I wouldn't be able to accelerate in 3rd before. With the MAP sensor disconnected, the gauge on Torque Pro reads 0, KOEO, and I get ~10-12 PSI of boost, but I still don't feel like this is all the truck should be putting out. I don't have excessive black smoke at WOT, but there is a small amount that I can see with the mirror pointed at the tailpipe. However, I am confused how the computer is getting readings "from" the MAP when it is disconnected.

I tested the MAP voltage, and based on the specs that I've seen here, the voltages that it is outputting are exactly where they should be for the elevation, about 1.2 V from the signal wire to the ground wire on the sensor, and the 5V reference voltage across the two outside pins is dead nuts on.

There are indications on the truck that it had a multi-position tuner installed at one point, a hole in the dash that is right where I would place the selector, and I know that the guy that i bought it from had a 'flash' style tuner on it, that I opted not to buy when i bought the truck, but he used it to return it to a "factory tune". Unfortunately, I don't know what brand the tuner was.

I'm looking for next troubleshooting steps, as I don't want to start "Parts swapping"

I'm also curious if this truck is supposed to have a barometric pressure sensor, and what the PID is, and if the lack of that is causing my issues, the 12.7 EBP -14.7 Sea level ambient PSI is way to close to the -2.1 PSI that I am reading on the MAP to be a coincidence.

Is it possible that one of the chips/flashes screwed the programming in the computer, causing all my issues? Can a dealership re-flash it for me to a known good factory tune?

I don't think that I have the other related issues, the EBP pressures look good, but I am planning to pull that apart and clean it out, just for fun. I also think that my EBV system is working correctly, as it kicks in durring winter, RPM's run about 1200 cold, but not during the summer.

I know that I need a new ICP sensor, and I'm going to pick that up at my local dealership tomorrow, and I'm going to ask if I can plug a MAP off the shelf in, and see what it reads on the OBDII (Fingers crossed). If i see that it fixes the readings, I have no problem purchasing it, but I don't think that is my problem, because my voltages are where they are supposed to be.

I'm also planning to pressure test the pressure side of the turbo to see if there is any loss there, but there is obviously a computer/sensor issue that needs to be addressed also.

Thank you in advance for any and all input! I'll be happy to perform any necessary tests, provide any necessary information, and if there are any better diagnostic tools, price allowing, I"m willing to purchase them. Most importantly, I'm here to learn!

Most of the information that I have compiled sofar is from this form, so I hope that not only can we solve my problem, but help someone else solve theirs in the future!

You guys are awesome, THANK YOU!

Thomas

 

The early 99s have a separate Barometer sensor, late 99 to 03s have it on the PCM

A few things to check, is the MAP line clear of oil?
Some have reported oil pooling in the line after T-ing in a boost gauge on the MAP line which changes it's length and angle, then it doesn't drain CCV vapors out, which pools and blocks the sensor readings

Another thing to check is the EBPV, make sure it isn't shut.

Waste gate actuator c clip still on? If the MAP doesn't read boost it won't start adding more fuel.

Your signs do point to a bad MAP, but check the free fixes before you throw money at it

 

I had a MAP sensor fail. Rare, but it happens. I hate to suggest you replace the MAP, it ain't cheap. Since your -2 boost (not MAP) is enough of a concern to say dump it, plus your improved results when it's unplugged says only three possibilities:

• MAP tube from the spider is unplugged or leaking.
• Bad MAP sensor.
• Zero boost (Gawd forbid).

I've lost boost for real recently, with a grenaded turbo. I was towing my 8,000 boat in the mountains when it happened, so the drive home was slow - but smokeless. When I compare my experience with yours, the first two possibilities above come to mind.

 

Thanks Guys! Since writing last night, I have ruled out my MAP, turns out I had an operator problem with the Torque Pro App, and had a gauge that was labeled MAP, but wasn't actually the MAP, it was the [FORD]Boost (Ford Specific) gauge from the ford pack, subtracting the BARO(), with a default 14.7 value, to get a "boost" number, hence the negative. I found the 'real' MAP' gauge, and it reads as I would expect it to. 12.7 PSI KOEO, right in line with the rest of my pressure sensors. I also found a custom PID config that got me a Barometer reading from the truck. This also looks absolutely correct.

I'll pull the MAP line tonight and check that it is clear, and this weekend I'll look at the EBPV system, and the EBP tube to check for obstructions. I suspect the tube is fine, my PSI ranges from atmospheric to ~35PSI WOT at near redline. I'm also going to put in my new ICP sensor, to replace the one that is oozing out of the plug, readings are still good, but I know it needs replaced.

 

I finally had some time today to pull the truck apart a little bit today, and found a couple things. One of the blue intake boots, passenger side top, has a small tear in it. I think that it is close enough to the end, under the clamp, that it won't make any difference, but I'll get a full set of replacement blue boots. I figure if one is torn, the rest aren't too far behind. I also found one of the clamps on the orange boots that goes from the intake spider to the engine may have slipped resulting in a boost leak. I got that all situated, but at the very least I want to clean everything and actually see oily new oily residue sneaking out. I may replace the orange boots also. I looked at the boost line that goes to the MAP sensor, and it seemed intact, but years of oily air has degraded the rubber, and it may as well be a hard line at this point. I'll get a replacement for that this week. Is fuel line sufficient for this, or is there a special line that I should get?

I did get to replace the ICP sensor, and will see it there is any change with that. As I said, it was oozing oil, but the readings still looked good.

The wastegate actuator all seams to be intact, and I can't move it by hand. I haven't tried pressurizing it manually to see if it actuates correctly yet, but I would like to try that also.

Last, I looked at the EBPV system, as best I could when it is 90 degrees out, and it all seems to be functioning correctly, the lever was up against the stop, and moved easily, except for LIGHT spring tension from the linkage/actuator. I went ahead and disconnected the actuator, and wired the valve open anyway, since I was already that deep, but first impressions, I don't think that it made any difference.

I didn't have time to pull the EBS out and clean the tube, but that is still on my list, as is pulling the intake off, inspecting and spinning the turbo by hand to see how it looks/feels.

I don't know if any of this information will give anyone any other ideas, but I appreciate everyone being a sounding board!

Happy Labor Day!

 

For the MAP line I'd think any properly fitting vacuum or fuel hose will do.

Do they still make vacuum hose?

Call Clay at Riff Raff and get a set of boots, T-bolt clamps, and plenum reinforcers. Boot problems solved.