Too much vacuum?

micahd

Registered User
Hey guys! Recently, my '95 (automatic) started hesitating on acceleration and worse when wide-open. I have not checked the fuel pressure yet but noticed that the past 2 days, my boost gauge shows a vacuum of more than 30 (pegged) when I let off the gas. It had never gone past 20 that I know of. The boost side is less than 5 when accelerating. At idle, the vacuum is at 20. Can fuel pressure do this or is it possible my supercharger is crapping out? I admit, I'm a re re when it comes to supercharger issues. Can timing do this?

My check engine light has always been going on and off since I bought the car 3 years ago. Engine was replaced 2 years ago. When the supercharger was pulled, the blades looked like new.

Thanks in advance for any help you can provide.
 
Pull the codes. If you need help on how to do that let us know. Paper clip and a piece of paper and pencil is all that is needed provided the person watching the blinks can count.
 
Off
124
175
176
181
185
189
214

Running
538
536
632

I have a cheap engine code tester (Innova 3145) that I used and didn't have a 2nd person to help test. Besides, the scanner didn't tell me to do anything such as reving the engine, turn steering wheel, etc.

The MAF sensor was replaced in April. Last year, I replaced the IAC and TP sensors. I have not changed the O2 sensors. Harmonic balancer was also replaced last year.

When I started up the scanner, it said 4 Cyl. That has me nervous.
 
per Ddubb

538 - System did not recieve a Goose test ( Dynamic response test )
632 - Engine ID / Goose test not switched
^^ could be user error for these depending on how they did the KOER test
 
The list of the first ones are stored codes. Saying everything from a bad DIS on down the line.

I would unhook the battery for about 30 minutes to an hour and plug it back in and see if any codes are still there and then run the car and see what codes come up, so you know what the new/current codes are.
 
Nope. That's why I mentioned that I was doing the test alone. I wasn't inside to press the pedals, turn the steering wheel, OD switch, etc. I was hoping that it was a user error. :)

I think I'm going to try to run the cylinder balance test tonight if I can do it right.
 
The list of the first ones are stored codes. Saying everything from a bad DIS on down the line.

I would unhook the battery for about 30 minutes to an hour and plug it back in and see if any codes are still there and then run the car and see what codes come up, so you know what the new/current codes are.

Yeah, I'll try to clear them too tonight. Supposedly my scanner can do that.
 
From this PDF, this is how you do the KOER test without having access to a tool that tells you exactly what to do.
http://fordfuelinjection.com/files/self_test.pdf
The KOER test is the next step in the diagnostic procedure. In order to initiate this test, with the ignition switch in the off position, ground the STI terminal. Now, start the engine. After a few seconds, the engine speed will increase momentarily and the “Check Engine” light will flash.The number of flashes will indicate the number of cylinders. Two flashes indicates a four cylinder, three indicates a six cylinder, and four indicates an eight cylinder engine. After you receive this verification, the ECM is looking for you to apply and release the brake pedal, turn the steering wheel one half turn, and toggle the over drive switch (if equipped). After these inputs by you, the ECM performs additional tasks in order to test the engine systems. The ECM changes the air/fuel mixture to test the oxygen sensor. Idle speed is changed to check the idle air bypass valve. The EGR system is activated while the ECM looks for a change in engine response. If the vehicle is equipped with an air pump, air is diverted upstream to test control valve operation. At this point the ECM will flash the “Check Engine” once to indicate to you that it wants you to snap the throttle. Snapping the throttle will help the ECM to check the operation of the Map sensor,Throttle Position sensor, Mass Air Flow sensor, and, if equipped, the Knock sensor. After this sequence, any fault codes will be transmitted through the “Check Engine” light in the same manner as the KOEO test. Fault codes that appear indicate a problem that the ECM detected during that particular test. Fault codes as a result of this test do not need to be erased. If the problem is corrected, the next KOER test will not display that code again. If there are no fault codes detected for any of these tests, you will receive a pass code of 11 or 111, depending on the system used in that vehicle
 
http://www.troublecodes.net/Ford/

Based on codes 175, 176, 181, and 189, it sounds like the car thinks it is running super lean at times.

Bear in mind that a misfire allows more unburned oxygen into the exhaust, and the computer will read that as lean running, when it's actually not.

Code 214 - I think that is cam sensor related. (Not sure.) I would try unplugging the cam sensor (and making sure the wire harness is not in the belts), then starting the car and seeing how it runs. It may take a few tries to get it to start without the cam sensor.

Codes 124 and 185 are related to fuel-air control. Any chance that you might have a blockage in your intake tract? Or maybe the TPS is worn out? The TPS is easy to test with a voltmeter, with key on and the car not running.
 
Thanks guys. I'll try to test these over the next couple of days. The error codes are the same I've had for the past few years. The check engine light is just more consistent now and the hesitation on acceleration is new. Of course, it lacks some power too.

The TPS was replaced last year because I thought that would fix that error but it didn't. Wires look good to me but not saying that there isn't a break somewhere on the inside. I may break down and replace the O2 sensor. I have just been dreading it because they can be a pain in the buttocks. The MAF sensor was replaced in April. I am probably due for new plug wires.

Also, I failed to mention that I believe I have an exhaust leak but wouldn't think the sensors could pick up anything from that. I have been wrong before. There's a patting sound underneath the car that's stronger on the driver's side. I just got some ramps so I can look for it.

This is my daily driver car so I tend to procrastinate on the bigger repairs because I can't be without a car.
 
Well, I wouldnt read much into the codes at this time until they are cleared.

The exhaust leak could be the reason it is saying it is lean when it is not, but again until the codes are cleared and the engine ran I wouldn't even try anything until that was resolved.
 
Sorry for the delay. I have been super busy lately. I cleared the codes and re-ran the tests. Everything is the same except I have 2 additional codes now. 171 and 172 are showing also. I ordered another throttle position sensor and it should be here tomorrow. If that doesn't work, I will replace the spark plugs and wires. I did check the fuel pressure and it seems to be fine. I may also crawl under the car this weekend and see if I can pinpoint the exhaust leak. I know I'll need to replace it, regardless.
 
im almost lead to believe you have a faulty gauge, the most i can yank on decel is 25 and thats with downshifting in my 5spd

at idle she sits right over 20 700ish rpm
 
im almost lead to believe you have a faulty gauge, the most i can yank on decel is 25 and thats with downshifting in my 5spd

at idle she sits right over 20 700ish rpm

I hope that's all it is. I need to pull the cluster to change the odometer gears anyway so I'll look at it and probably replace it. Yeah, it just started doing that but it started at the same time I started having the hesitation problem so I figured they were related somehow.
 
im almost lead to believe you have a faulty gauge, the most i can yank on decel is 25 and thats with downshifting in my 5spd
at idle she sits right over 20 700ish rpm

Well, it appears that you were right about the gauge. On my way to work this morning, the needle fell out of the gauge. :rolleyes: I guess I will definitely be pulling the cluster out soon.
 

Attachments

  • 2011-08-22 07.08.29.jpg
    2011-08-22 07.08.29.jpg
    97.7 KB · Views: 41
Over the weekend, I replaced the TPS and cleaned the throttle body. I also cleaned the MAF sensor even though it was replaced in April. Car accelerates great now. The check engine lights are still on though. Same codes. Next, I'll crawl under the car sometime this week to see if I can find the exhaust leak.
 
Back
Top