Service slants

Motor, Oct 1999 by Juran, Ken

Dodge

Lack of power. With more than 400 hp, it's hard to believe but there are some 1996-97 Dodge Viper GTS Coupes and 1997 RT/10 Roadsters out there that may develop a lack of performance at wideopen throttle. Luckily, though, it's a simple mechanical ailment that causes the trouble. Inspect the throttle cable bracket. If you find it in the farthest rearward position, remove the air inlet duct. Then, with the accelerator pedal to the floor, take a look at the position of the throttle blades. If they're not sitting wide open, you need to install a new throttle cable bracket (Part No. 0484&S36AB) and perform an adjustment.

The adjustment requires use of a .039-inch (1.0mm) feeler gauge placed between the accelerator pedal and its stop plate on the floor. Make sure the throttle blades are open all the way before tightening down the throttle cable bracket to 95 in.-lb.

GM Truck

No upshift, stuck in 2nd. After a cold start, some 1994-95 Chevy and GMC C/K-, G- and P-body trucks and some 1996 G- and P-bodies-all equipped with the Hydra-matic 41-SOE automatic-may suffer from no upshift. Engine possibilities are the 4.3-liter V6, 5.7and 7.4-liter gasoline V8s and the 6.5liter turbodiesel V8.

In combination with this, a DTC 87 may set intermittently, causing the PCM to keep the trans in 2nd gear limp-home mode. According to GM, this is all caused by a commanded shift to 3rd or 4th that took longer than 2 seconds at a minimum 25% TPS reading, which set the DTC 87.

If you can't come up with anything during routine diagnostics, the truck will need its EPROM replaced. The new EPROM will have a DTC 87 shift time parameter of 4 seconds (2 seconds longer than before) and a code-enabling temperature of 68F. Note that in 1995, the diesel engines received a change in fuel injection timing pumps that required a new EPROM. The current service pump will work on prior models, so be sure to match the EPROM with the proper fuel injection timing pump on the diesels.

To get the new EPROM, it looks like you'll need the broadcast code and scan ID of the old one. There are some 80 different chips to cover all the applications.

Ford

Stall, surge at speed. The PCM is responsible for the symptoms described below on some 1996 Taurus/Sable models with the pushrod 3.0-liter V6 and engine calibrations 6-IOA-R07, R10, RII, R12; 6-lOB-R06, 1111, R12; 610SR07, RIO, Rll, R12; and 6-10TR06, Rll, R12.

These cars may stall when put in Drive or Reverse with a cold engine, and they may surge on the road between 35 and 45 mph. Either a PCM reprogramming or replacement is necessary There are just four new calibrations that take the place of all the ones listed above. Respectively, they're 6-10A-R12, 6-lOB-R12, 6-lOS-R12 and 6-lOT-R12.

Don't forget to pick up an Authorized Modification Decal, describe the repair on it and stick it underhood for future reference.

Infiniti

Towing the QX4. Here are a few tips on towing the QX4 sport/ute and its capable 4WD system. If possible, use a flatbed or a combination wheel lift/dolly to prevent damage to the driveline. Never use a sling-type towing harness, because the bumper fascia will get mauled. If the truck will be towed at more than 30 mph or for more than 40 miles, either all four of the QX4's wheels must be off the ground or the front and rear prop shafts must be removed to prevent transfer case/transmission damage.

If speeds will be less than 30 mph for less than 40 miles, it's okay to leave the truck on the ground. But all of these conditions must be satisfied: 1. all four wheels on the ground; 2. parking brake released; 3. transfer case shift lever in the "H" position; 4. transmission shift lever in the "N" position; 5. tow only in the forward direction. Infiniti says towing the QX4--or any automatic transmission-equipped Infiniti, for that matter-backward with all four wheels on the ground may cause serious and expensive transmission damage.

Isuzu

Spark plug tube replacement Here's Isuzu's recommended procedure for replacing a cylinder head spark plug tube on the 6VD1 3.2-liter SOHC V6 found in 1992-97 Troopers and 1993-97 Rodeos. To get the old tube out, use Kent-Moore tool No. J-41730 and slide hammer No. J-2619-01. Thoroughly clean the spark plug tube joining area, but not with a power wire brush. Remove all the varnish, soot and old adhesive. Apply Loctite 290 or equivalent to the outer edge of the new spark plug tube. Then install it using the Kent-Moore J-41730 and a plastic-face hammer.

Finally measure the spark plug tube height from the base of the camshaft bracket. It should be 64 /-0.5mm (2.52 /-02 inch).

Audi Suspension changes. There have been a number of changes to the front suspension design on 1996 and newer Audi A4 and A4 Quattro sedans. Here's a summary of how these changes affect suspension service:

The three mounting bolts for the upper control arms/suspension strut mounting bracket take 55 ft-lb. The main hub bolt was changed from a conventional hex head collar type to a hex socket collar type. This bolt should always be replaced during service, but its okay to mix the old and new style bolts. When you tighten these bolts, the car should be sitting on its wheels. The M 14 bolt takes 85 ft-lb plus a quarter-turn while the M 16 bolt takes 140 ft-lb plus a quarter-turn. There are four M10x70 bolts per side holding the front subframe to the body. These must always be replaced, and they take 52 ft-lb.