Wednesday, November 29, 2006

Code P0302 causing misfire for 1996 Pontiac Grand Am with 2.4L engine




Question:

Four days ago, my Grand Am started misfiring and when I scanned it, I got code P0302 cylinder #2 misfire. Using your earlier advice, I removed the top valve cover and run my own plug wires and switched #2 cylinder with #3 cylinder but the misfire stayed at #2. Switching the ignition coils also made no difference. Because the vacuum hose going to the fuel regulator was wet, I changed the fuel regulator and again made no difference. All the compression readings were over 200 psi and I am losing my wits on what to do next. Your help will be much appreciated.

ATS Adviser:

Since you got the valve top cover out, you might as well do a balance injector test as described in ATS Course. Another quick way to do this is to switch injector #2 to another injector like #4. Then make sure the engine is warmed enough and see if the misfiring will remain in #2 cylinder. If it moves to cylinder #4, you know pretty well that the problem is the injector.

ATS tip:

The fuel regulator although defective in your case, will not cause misfiring. It will make your engine fuel mixture to flood or rich though and cause hard long starts.

Monday, November 27, 2006

Code 181 for 1994 Ford Escort 1.9L accompanied by hesitation and cutting out.


Question:

My mother's Ford Escort would hesitate only when running at highway speeds as if the engine is running out of gas. When this happens, the engine would also stall and finally quit. It will re-start but it has no power. She had the IAC (Idle Control) valve replaced but the problem remains and she asked for my help. I plan to do a major tune up like spark plugs, wires and fuel filter. What bothers me though is when I scanned it, it has code 181 which showed cruising rich and bank 1 lean. Is this problem serious? Can I fix this myself?

ATS Adviser:

First and foremost, check first if you have a vacuum leak which can cause your engine to run lean. Next is to check the voltage readings of your oxygen sensor and see if it fluctuates (see ATS courseware). This sensor seems to be a common problem on this model especially with this code and symptom of hesitation. You can also check these:

1.) Service the mass sensor for dirty wire elements
2.) Check the fuel regulator for diaphragm fuel leakage
3.) Check pcv valve for crack that would cause vacuum leak

You should be able to do these checks by yourself if you read the ATS lessons given to you but I would concentrate your effort to check if the voltage reading of the oxygen sensor is not stuck (this will show that the sensor is defective).

ATS Tip:

A bad running oxygen sensor can disrupt your fuel mixture and would cause hesitation and loss of power.

Thursday, November 23, 2006

P0340 code for 1997 Toyota Camry with 2.2 L engine




Question:

My uncle's 97 Camry has the dash check engine light coming on all the time. Found code P0340 which stands for camshaft position sensor fault. He changed the camshaft sensor and the engine ecm (computer) but the light would come up after driving it for a few miles. He asked me to help him and I just want your assistance before I see him. Note: This vehicle has a lot of mileage on it.

ATS Advisor:

If the vehicle has too many miles and the timing belt has not been replaced, most likely the belt is either loose or has skipped a tooth. When this belt is loose or out of timing, the ecm will get an erratic signal from the camshaft sensor and will trigger this code. This is usually occur with rough idle and lost of power. Try this first and if this won't work, pull out the distributor and check for worn drive gears.

ATS tips:

If timing belt is out of timing, the vacuum reading is usually low (15 inch or lower) accompanied by low compression reading.

Instructions for changing the timing belt are available from ATS if you are a member.

Wednesday, November 22, 2006

BCM (body control module) Testing Summary




When performing test for your body control module (bcm), here are some quick tips in testing this module:

Get hold of the bcm wiring diagram from ATS. Using the bcm diagram, you can identify all the components that being controlled by the bcm by using the wiring colors associated with the part or component. A lot of times, the location of the component is described in the wiring diagram. BCM components usually include lights, power mirror, window and door locks, anti-theft, windshield wiper system, radio, instrument cluster, horn, all vehicle openings like trunks, defogger, power steering, AC, cruise control and other accessories.

The first test of the bcm is using a scanner. It will tell you right away which part of the bcm system is malfunction. It can also isolate the particular circuit in the bcm to narrow down your test. Remember: bcm code is not the same as the engine code.

To test the bcm, start by checking the ground pins for voltage which must not be higher than 0.250 volts. If it does, it means there is a short in the wires or one of the components. To verify, unplug the components one of the time until the voltage reading returns to normal.

Make sure all connections to the bcm and components are tight and not corroded.

The BUS plus and minus communication pins at the bcm can be checked and it should measure about 2.5 volts (ask ATS for the exact voltage for your vehicle) with key on. If none or higher voltage reading, it indicates an open wire or defective bcm or component. Again try to unplug the component one at a time to test.

ATS tips:

When working with bcm, always read all the blog posts by searching the word "bcm" on the top left corner bar of this blog and click "search this blog" beside it.

BCM when replaced needs to be reprogrammed by the dealer when bought new. When buying one from the salvage yard, make sure it is the same match for your vehicle. Sometimes, the bcm does not include the alarm system and can cause future problems.

Monday, November 20, 2006

P0303 code for 1998 Ford Taurus with 3.0L engine.




Question:

My check engine light keeps coming on and got a code P0303 misfiring code on cylinder #3. I checked the compression on this cylinder and it is comparable with the rest. I have no vacuum leak and got 18 inch when I measured it. I swapped the injectors from #3 to #1 cylinder and after a week, the code still returned for #3. Finally, this code is also intermittent and I am about to bring it to the dealer if you have any suggestion.

ATS Adviser:

Going by ATS database, one fix that you might have missed is the ignition coil pack. Have you tried switching the plug wires too? If the coil pack is borderline defective, it will run OK and might test well if you measure it with a voltmeter. However, if it is used for a few days especially under load, it might start to falter and show you the code. That would be the test I would do if I were you before going to the dealer.

ATS Tip:

You can also use an electric air heater and apply it to the coil and see if the part will fail.

Saturday, November 18, 2006

1997 FORD F150 P0401 EGR Flow code with 5.9L engine




Question:

As per your ATS instruction manual, I changed the egr valve, dpfe sensor, egr solenoid including the blowing of air passages of the egr system of this engine yet this same code keeps coming back. Am I missing something? I also reset the code but the check engine light with the same code is on all the time.

ATS Adviser:

Although you replaced all those parts, you did not indicate if those parts are from Ford which makes a lot of difference. Sometimes when you use 'aftermarket" parts, the quality might not be comparable. Also, when you said you blew the passages of the egr system with air, did you remove the throttle body? The carbon build up inside the intake manifold ports is very difficult to remove unless you take out the throttle body.

ATS Tip:

When the same code appears, it shows the problem is not solved like restricted flow.

Thursday, November 16, 2006

1997 Intrepid wiper motor won't stop even with key off: No codes




Question:

The windshield wiper motor will not stop until the fuse is taken off. I am scratching my head here because I thought replacing the wiper motor would fix it but to my surprise, it did not change anything. Suggestions?

ATS Adviser:

Symptom such as yours could be fixed by replacing the wiper motor because of a bad park switch located inside the wiper motor. However, a lot of this problem is also caused by a bad ground at the wiper motor housing and you can correct that by running a ground wire direct from the battery negative to the wiper motor housing. Assuming that won't fix it, replace the multi-function switch at your steering wheel.

ATS tips:

To verify the integrity of the wiper components, ATS can supply you the complete wiper motor wiring diagram so you can test the circuit.

Wednesday, November 15, 2006

2000 Grand Prix with 3.8L engine intermittently quits after driving for 5 miles: No codes




Question:

This car quits after being driven for 5 miles. It starts right away when re-started but I am puzzled because there is no code when scanned. I cannot check the spark or fuel signal because this happens quickly and there is no changed even after I changed the ignition module. Please help.

ATS Adviser:

Most of the symptoms you gave points to a defective crank sensor. It is located behind the front crank pulley which must be removed to access the crank sensor. Before doing it, make sure all the wiring connections to the sensor is not shorted. After replacement, reset the code and take it for a road test to confirm the fix.

ATS tip:

If after the sensor is replaced and problem re-occur, you need to check the ecm (computer) wiring terminal integrity of the ground and reference voltage signals so we can check that too.

2000 Grand Prix with 3.8L engine intermittently quits after driving for 5 miles: No codes




Question:

This car quits after being driven for 5 miles. It starts right away when re-started but I am puzzled because there is no code when scanned. I cannot check the spark or fuel signal because this happens quickly and there is no changed even after I changed the ignition module. Please help.

ATS Adviser:

Most of the symptoms you gave points to a defective crank sensor. It is located behind the front crank pulley which must be removed to access the crank sensor. Before doing it, make sure all the wiring connections to the sensor is not shorted. After replacement, reset the code and take it for a road test to confirm the fix.

ATS tip:

If after the sensor is replaced and problem re-occur, you need to check the ecm (computer) wiring terminal integrity of the ground and reference voltage signals so we can check that too.

Tuesday, November 14, 2006

1996 Ford Taurus ps pump shooting oil as soon as the car is started: No codes




Question:

My sister's 1996 Ford Taurus has a weird problem: the power steering pump shoots oil as soon as the engine is started. We installed a new power steering pump and the same thing happened. How do you fix this?

ATS Adviser:

This car's steering system uses a rack and pinion and most likely, it is shot and not allowing the oil to pass through. When that happens, oil pressure builds up in the ps pump and is forced to release it on the pump itself. This is what you are seeing during the release. To fix, replace your rack and pinion.

ATS Tip:

Make sure to flush the entire steering system after the rack and pinion is replaced.

Monday, November 13, 2006

Code 44 on 94 GM Safari with 4.3L VORTEC engine




Question:

The last few days, I am getting poor acceleration on this engine. When I scanned the codes, I got code 44 -lean exhaust. I have done a quick tune up consisting of spark plugs and wires including the fuel filter. I also changed the oxygen sensor and all of these did not seem to help. It used to bog down once a week and now it is doing it every other day. What do I do? (Note: I also tested the fuel pressure and it was 56 psi at idle).

ATS Adviser:

The give away for the fix of this problem is the fuel pressure. Any vortex engine, the fuel pressure reading is critical. It should not go down below 60 psi or you will have this symptom. Your reading is low and you need to replace the spider injector located under your engine plenum. About 90% of the time, replacing the injector (see picture) will fix this problem. If not, check the magnet of your distributor shaft.

ATS Tip:

ATS can supply you the step by step procedure in replacing the centralized spider injector if you are a member.

Thursday, November 09, 2006

1994 Ford Ranger Engine surges when AC defogger is tuned on: No Codes




Question:

My engine runs OK as long as I don't use the front dash defogger. If I set the AC button to floor setting, again engine runs fine. I scanned for codes and there is none. Can you give your insights on this problem?

ATS Advisor:

When you set your AC button to the defogger mode (see picture), the AC is actually activated and is controlled by Freon pressure which is monitored by your AC computer. When this happens, the AC computer signals the engine computer to raise the rpm to prevent the engine from stalling. However, if Freon pressure is low, the AC clutch is de-activated which cause the AC system to stop and rpm goes down. With these two modes, it will create a high or low rpm or surging condition. Try testing your Freon level and top it up with freon if possible.

ATS Tip:

Putting your AC setting to the floor mode de-activates the AC system causing your engine to run normal because the AC computer is not controlling the engine rpm anymore. ATS can supply you the Freon pressure specs for this vehicle.

Monday, November 06, 2006

Code 35 erratic engine idle for 1993 Pontiac Grand Am with 2.3L engine




Question:

My wife's Grand Am has a rough idle and it has code 35 when scanned. As per ATS info, most of this problem is solved by fixing a vacuum leaks.Is there a quick way to do this?

ATS Adviser:

Most vacuum leak can be found by runnning the engine at idle and using a propane bottle (use for soldering cooper tubings), by feeding raw propane gas on all vacuum lines and intake manifold gaskets. If you hit the vacuum leak, the engine rpm will usually change indicating a vacuum leak. Some mechanics use carburator cleaner spray can in place of the propane but can pose a fire hazard when sprayed on exhaust. To be safe, you can also spray mist of water from a spray bottle for the same effect. On most 1994 Grand Am 4 cylinder engines, the engine leak can be found on the corner of the intake manifold.

ATS Tip:

After finding and repairing the vacuum leak, reset the code to confirm the fix.

Sunday, November 05, 2006

1993 Cavalier 2.2L stalls at stop lights but will re-start in 15 minutes: No codes



Question:

My daughters car is stalling at stop lights and if she waited for 15 minutes, it
would start again. I changed the spark plugs and fuel filter and the stalling
still happens. I scanned for codes and there is none. How do I fix this?

ATS Adviser:

If you have to wait for 15 minutes before it starts, always check for spark at your plugs. If none, the problem is usually your ignition parts. Crank sensor would be the first choice even if it tested OK. You can check that by hooking a test light from your battery positive and tap the purple white wire at your ignition module connection (do this with key off). If the injectors start clicking when you touch the injectors, the crank sensor is defective and the module is OK. Otherwise, replace both module and the ignition coil.

ATS Tips:

If no starts occurs after warmed up but re-starts right away and dies again after you put it in gear, the tcc sensor is defective. you can unplug it from the side of your trany and road test again. If symptoms stop, then it is definitely a tcc sensor problem.You can leave it unplugged but you might loose some fuel mileage.

ATS can supply you the ignition wiring diagram so you can trace all the wires and location of the ignition parts.

Wednesday, November 01, 2006

P0506 IAC code on Ford F150 with 4.6L engine.




Question:

My F150 pick up truck has a bad rough idle and would surge/stall at times. After scanning, I got a code P0506- Idle air control system rpm fault problem. Does this mean I have to change the IAC motor?

ATS Advisor:

As per wiring diagram, there is no IAC motor for this engine and I suspect you have an error code. You can try resetting the computer by disconnecting the battery negative terminal or using your scanner. For your rough idle, I would try testing for vacuum leak by using a smoke machine recommended by ATS. The rpm on this is controlled by the electronic throttle control motor located in the throttle body with the help of the electronic throttle control module located in the accelerator pedal bracket. However, since there is no code on these TP sensor and module, I would try cleaning first the TB plates with intake spray and then blow it dry with air. The throttle plates are known to build up carbon deposits and causing rpm problem.

ATS Tip:

There is an extended warranty for emission on this engine and you should contact Ford to verify it.