Question about 2000 GMC Safari

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2000 Safari, engine/trans stumbles under load. Already replcd...

... Distributor cap/rotor, Ignition wires, O2 Sensors (#2 position, right and left), Air flow Sensor, and fuel pump/filter. The results are the same. Two transmission shops say that the trans. is fine. The problem is increasing, it started with a flat spot upon acceleration, now it's complete shuddering/shaking upon acceleration seemingly wanting to die. I've theorized that it might be a lack of appropriate timing under a load therefore pointing at either the coil, ignition module, or the powertrain control module (PCM), Can anyone help me out. My mechanic is at a loss since his scanner just indicated the sensors already replaced.

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  • rwgemser Feb 06, 2009

    Thank You for your response. What are TSB's? How about my theory regarding the coil, ignition module or Powertrain Control Module? Would these items, under load, also create the symptoms that it's displaying?

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I saw in another post that the Ethanol was causing the rubber pipe in the fuel filler to dissolve which caused the injectors to get plugged, also the ethanol was causing the plastic lines on the injector octopus to get brittle and crack. This is also a problem with plastic fuel tanks, which causes them to clog up the engine, injectors, and valves.

Posted on Nov 30, 2011

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Other problem areas to check are a clogged catalytic converter and rear axle gear oil level (Astro/Safari axle seals leak causing shuddering under load and eventually seizing).Also GM's have had strange intermitent engine and trans problems that dissapear after replacing the main fuses. Check with a GM dealer for TSB's for your truck.

Posted on Feb 05, 2009

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1 Answer

Engine Rotates (acts as it will start) won't fully turn over.


Did you replace the TPS (throttle position sensor)?? Try that if you haven't so. But if you did that already, and still getting the same problem, I would suspect the fuel pump going bad.

Apr 12, 2014 | Cars & Trucks

1 Answer

Trying to figure out what the name of a part is


That would be the ignition coil, the part that creates spark at the spark plug. If you follow the electrical path from the coil wire to the distributor cap, and from there, the spinning rotor just under the distributor cap carries the path from the coil wire at the cap's center to the spark plug wires around the dist. cap, and through the plug wire to the spark plug.
The high voltage causing the spark is created in the ignition coil by the engine computer at the precise right moment signaling an ignition module to cut 12 volts current to the ignition coil. This causes the coil to internally build up high voltage which is passed through the coil to distributor cap wire. The computer knows the precise right moment to initiate spark from engine sensors, primarily the crank position sensor and the cam position sensor.

Nov 06, 2012 | 1999 Dodge Durango

3 Answers

I have a 1993 chev pick-up v6 4.3, i just installed new spark plugs,new plug wires, distributor cap and rotor button.All plug wires are back in the right position,and i used the firing order 1-6-5-4-3-2...


This diagram is for 1998-1995 Chevy 6 cylinder 4.3L engines.
Your got the firing order exactly correct, at 1-6-5-4-3-2, but here's the thing to double-check:
The distributor rotation is clockwise (note badly rendered arrow in picture).



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Since you probably got everything right, then you're left with really unusual/rare causes of
failure of the ignition system:
(a) rotor button misaligned/failing to make contact?
(b) rotor button not pressed onto distributor shaft far enough therefore failing to provide correct
proximity to distributor cap contacts when coil fires
(c) coil wire or contact loose/disconnected - press coil wire firmly down into distributor cap.
(d) distributor shaft of other damage caused during installation of rotor.
(e) spark plug wires defective from factory
(f) spark plugs defective from factory
(g) battery low - may need a charge to start
(h) ICM (ignition control module) failure - hook up your HEI (high energy ignition) tester, and
watch the quality of the spark on each cylinder.
(i) fuel problem? If spark is being properly delivered, its gotta be a fuel problem...
(j) distributor cap not screwed down flush to top of distributor? maybe just on one side?

Inspect the inside of the distributor cap - if there are lots of little metal bits all over the inside
of the distributor cap, then you know you have a misalignment of some type in there, and the
rotor and cap are destroying each other. normal operation will throw a quota of spark-ed off
metal bits inside the distributor cap, but since your cap is brand new, your attempts to start
the engine should have rotated the distributor so few times, you should see no metal debris.

Inspect the distributor cap contacts to see if any spark marks are more of less in the middle
of the cap's proper "contact zone". If not, you've diagnosed an internal misalignment, which
you know how to correct.

Sep 14, 2011 | Chevrolet 1500 Cars & Trucks

4 Answers

How to replace an ignition rotor to a 1988 Ford Escort


Your vehicle may be equipped with either of the following ignition systems, depending on the year and engine combination:
* 1981-82 1.3L and 1.6L engines: Dura Spark II Ignition System
* 1982-85 1.6L Non-EFI and 1986 1.9L Non-EFI engines: Thick Film Ignition I (TFI-I) System
* 1983-90 1.6L EFI and 1.9L EFI engines: Thick Film Ignition IV (TFI-IV) System

  1. Disconnect the negative battery cable.
  2. Remove the distributor from the engine.
  3. Place the distributor assembly on a workbench.
  4. Remove the two TFI ignition module retaining screws.
  5. Pull the right side of the module down the distributor mounting flange and then back up to disengage the module terminals from the connector in the distributor base. The module may then be pulled toward the flange and away from the distributor.
Do not attempt to lift the module from the mounting surface, except as explained in Step 3, as the pins will break at the distributor module connector.


To install:
  1. Coat the baseplate of the TFI ignition module uniformly with a 1 / 32 in. (0.8mm) of silicone dielectric compound WA-10 or equivalent.
  2. Position the module on the distributor base mounting flange. Carefully position the module toward the distributor bowl and engage the three connector pins securely.
  3. Install the retaining screws. Tighten to 15-35 inch lbs. (1.7-4.0 Nm), starting with the upper right screw.
  4. Install the distributor into the engine. Install the cap and wires.
  5. Reconnect the negative battery cable.
  6. Recheck the initial timing. Adjust the timing, if necessary.

Hope helps.

Sep 10, 2010 | 1988 Ford Escort EXP

1 Answer

Where is the cam sensor located


Removal & Installation 2.2L Engine To Remove:
  1. Lift the vehicle.
  2. Remove or disconnect the following:
    • Right wheel and tire assembly.
    • Camshaft position (CMP) sensor electrical connector. gm_truck_s10_cmp.gif

    • Bolt and CMP sensor.
To Install:
  1. Install or connect the following:
    • Camshaft position (CMP) sensor and bolt.
      1. Torque to: 7 ft. lbs. (10 Nm)
    • CMP sensor electrical connector.
    • Right tire assembly.
  2. Lower the vehicle.
4.3L Engine To Remove:
  1. Remove or disconnect the following:
    • Spark plug wires and ignition coil wire from the distributor 4.3L Distributor CMP electrical connector gm_trk_sil15_02-04_43_dist_cmp_elect_conn.gif

    • Camshaft position (CMP) sensor harness connector from the distributor
    • Distributor cap screws 4.3L Distributor cap removal gm_trk_sil15_02-04_43_dist_cap_rem.gif

    • Distributor cap 4.3L Distributor rotor screws removal gm_trk_sil15_02-04_43_dist_rotr_screw_rem.gif

    • Rotor screws
    • Rotor
    4.3L Align reluctor wheel slot with CMP gm_trk_sil15_02-04_43_algn_whl_slot_cmp.gif

  2. Align the square slot in the reluctor wheel with the CMP sensor 4.3L CMP sensor screws removal gm_trk_sil15_02-04_43_cmp_sensr_screw_rem.gif

  3. Remove or disconnect the following:
    • CMP screws 4.3L CMP sensor removal gm_trk_sil15_02-04_43_cmp_sensr_rem.gif

    • CMP sensor
To Install:
NOTE: Do not use the old cap, CMP sensor, and rotor screws. Use the replacement screws that have been coated with a thread locking compound.
  1. Insert the CMP sensor through the reluctor wheel slot
  2. Install or connect the following:
    • New CMP mounting screws and tighten the screws
      1. Torque to: 19 inch lbs. (2 Nm)
    • Rotor onto the reluctor wheel
    • New rotor screws and tighten the screws
      1. Torque to: 18 inch lbs. (2 Nm)
    • Distributor cap
    • New distributor cap screws and tighten the screws
      1. Torque to: 21 inch lbs. (2.4 Nm)
    • CMP sensor harness connector
    • Spark plug wires and ignition coil wire
  3. Test drive the vehicle to confirm the repairs
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Aug 17, 2010 | 2000 GMC Jimmy

1 Answer

What is the timing specs for a chevy 98 suburban V8 350 gas.


The ignition timing is not adjusted with a timing light or with the engine running, and to set the ignition timing follow these proceedures.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on top dead center. This "static" timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at top dead center.

1. Place the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing indicating the number one position.

3. With the engine on top dead center the ignition rotor should be pointing to the number one mark or notch that is on the distributor housing, if it is not then loosen up the distributor and turn the distributor until the ignition rotor is pointing to the mark or notch on the distributor housing and then tighten down the distributor, the engine should now be static timed.

If the distributor can not be turned enough to align the ignition rotor with the number one mark on the distributor housing, or the distributor does not set properly and will not allow the installation of the spark plug wires then the distributor is not installed correctly and is most likely a tooth off and it will need to be re-installed correctly. (The distributor should set like it is shown in the firing order diagram when it is properly installed)

Here is a firing order diagram to also help assist you.


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Aug 05, 2010 | Chevrolet Suburban 1500 Cars & Trucks

1 Answer

1999 silverado 4.3 cranks but no start can hear fuel pump, swaped out coil and crank sensor w/ known good parts no change, engine did start once after coil was changed ran rough and stalled and wont...


First check to see if full battery voltage is even getting to the "Pos" (+) positive side of the ignition coil when the key is in the "Run" position, and also that full battery voltage is getting through the "Pos" (+) or positive side of the ignition coil and over to the distributor ignition module

The ignition module and the pick-up coil/stator located inside of the distributor is what generates the signal that the ECM (Engine Control Module) uses to time and fire the fuel injectors, as well as the signal to run the fuel pump and the dwell signal timing to fire the ignition coil, and a faulty ignition module can cause any one of these systems to malfunction.

That does sound like a malfunction with the ignition module inside of the distributor, and you can remove the ignition module and have it tested for free at most auto part stores. If the ignition module does test out alright then the problem could still be in the pick-up coil/stator, (it can be tested using an ohm meter by dis-connecting the wire connector from the pick-up coil/stator and the ohm reading between the two wires from the pick-up coil/stator should be between 500 and 1500 ohm's, and both of the wires from the pick-up coil/stator should show an open loop or an infinite reading between each wire and ground) and if the pick-up coil/stator is found to be faulty then replace the entire distributor, or the distributor will have to be dis-assembled to install a new pick-up coil/stator.

If you do purchase a new ignition module be sure that it does come with a silicone grease or a die-electric compound because it is a heat sink and the ignition module will burn up without it.

To install the new ignition module first clean out the mounting surface inside of the distributor. Then completely coat the metal contact surface under the ignition module with a thick coat the silicone grease or die-electric compound and do not leave any of the metal contact surface of the ignition module un-coated with the silicone grease or die-electric compound, and be very careful not to over-tighten the ignition module or it will be damaged.

To replace the distributor follow this procedure;

The ignition timing is not adjusted with a timing light or with the engine running, and to set the ignition timing follow these procedures.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on top dead center. This "static" timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at top dead center.

Removal;

1. With the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing indicating the number one position.

3. With the engine on top dead center the ignition rotor should be pointing to the number one mark or notch that is on the distributor housing, Then make a reference mark of the position that the ignition rotor is pointing to (out on the engine or firewall) and the more precise you mark the position, the easier the installation of the new distributor will be. This will be reference mark #1.

4. Remove the distributor lock down bolt, (the lock down clamp will most likely be attached to the distributor and if so it should not be removed from the distributor) then slowly lift up on the distributor about three inches and note the direction that the ignition rotor turns, and when the ignition rotor stops turning then mark the position that the ignition rotor is pointing to (out on the engine or firewall) and then lift the distributor striaght up and out, and remove the gasket or any left over gasket material from the intake manifold. The more precise you mark the position the easier it will be to install the new distributor and an assistant might be helpful. This will be reference mark #2

Once the distributor has been removed it is important that the engine does not get cranked over by the starter or the crankshaft turned at all, or the reference marks will become useless.

Installation;

Be sure that the new distributor is complete with a new module and that there is a new gasket in place on the distributor.

1. Lower the distributor with gasket down into the distrbutor well and align the ignition rotor with the #2 reference mark and when the distributor gear engages the drive gear on the camshaft then the ignition rotor should turn to the #1 reference mark as the distributor sets all the way back down flush on the intake manifold.

2. Install and tighten the lock down bolt, and If the distributor is properly installed then the ignition rotor should be pointing to the #1 reference mark and the #1 position on the distributor housing with the engine on top dead center.

Replace the distributor cap and connect the spark plug wires, and see if the engine will start, if the engine does start and the check engine light does not come on (assuming that it was not on before) then the distributor is properly installed and there is no further timing requirements.

Let me know if you require any further assistance.



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Jul 31, 2010 | 1999 Chevrolet Silverado 1500

2 Answers

How to remove distributor on a 1998 gmc pick up with 5.0 engine, do I have to mark anything or just take off bolt and pull out.


You need to mark in 2 places. With the cap off mark the position of the rotor button on the distributor housing first. Then you need to make a mark on the distributor housing that will line up with a mark on the engine itself.
When you put the distributor back in back the rotor button up before you put it in because the cam gear will turn it ahead as it seats. For example, if the rotor button is at 3 o'clock then back it up to 1 o;clock.
Don't force the distributor down at the end because you can damage the end that drives the oil pump. Fidle and wiggle it as you push and it should line up and drop onto the oil pump. Also DON'T turn the engine over while it's out or you will have to retime the engine. Hope this helps.

Jul 03, 2010 | 1998 GMC Sierra

2 Answers

How do you set the timing on a 1998 GMC Sierra?


The timing is not adjustable and it is computer controlled, but the distributor must still be clocked in properly and static timed, and here is how it is done.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on top dead center. This static timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at top dead center.

1. Place the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing.

3. With the engine on top dead center the ignition rotor should be pointing to the mark or notch that is on the distributor housing, if it is not then loosen up the distributor and turn the distributor until the ignition rotor is pointing to the mark or notch on the distributor housing, the engine should now be static timed.

Jun 12, 2010 | 1998 GMC Sierra

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