CAMPAIGN: IDLE CO-ADJUSTMENT MAY EXCEED EMISSION STANDARDS

MODELS: 1985 and 1986 Chevrolet Sprint and Pontiac Firefly Models

TO ALL AFFECTED DEALERS:

DEFECT INVOLVED:

General Motors of Canada has determined that 1985 and some 1986 Chevrolet Sprint and Firefly models may have factory idle CO adjustment higher than specified limits. Consequently on some vehicles, idle CO was not the same as the certified vehicles and hydrocarbon emissions may exceed the Canadian Emission Standard.

VEHICLES INVOLVED:

All 1985 Chevrolet Sprint and Firefly models, as well as 1986 Sprint vehicles through VIN 808026 and 1986 Firefly vehicles through VIN 860326. Vehicles beyond these VIN's, which were produced on or after November 26, 1985, have correct factory idle CO adjustment.

All affected vehicles have been identified by the VIN listing provided to involved Dealers with this bulletin. Any Dealer not receiving a listing was not shipped any of the affected vehicles.

DEALER CAMPAIGN RESPONSIBILITY:

Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward.

Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory, or it is in your Dealership for service in the future, you should take the steps necessary to be sure the campaign correction has been made before reselling or releasing the vehicle.

Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the Dealer, and arrangements made to make the required modification according to instructions contained in this bulletin.

CAMPAIGN PROCEDURE:

Refer to Section 4 of the Service Policies and Procedures Manual for the detailed procedure on handling Product Campaigns. Dealers are requested to complete the campaign on all transfers as soon as possible.

OWNER NOTIFICATION:

All owners of record at the time of campaign release are shown on the attached computer listing and have been notified by first class mail from General Motors. The listings provided are for campaign activity only and should not be used for any other purpose.

PARTS INFORMATION:

As only approximately 60% of vehicles will require T-connectors, an appropriate amount will be shipped and charged to the Dealers involved to cover the anticipated requirements.

PART NUMBER DESCRIPTION QUANTITY ----------- ----------- -------- 52350705 T-Connector 1 per vehicle, if required

PARTS AND LABOUR CLAIM INFORMATION:

Credit for the campaign work performed will be paid upon receipt of a properly completed campaign claim card or RAPID terminal, transmission in accordance with the following:

Repair Code Operation Time Allowance ----------- --------- --------------- 2A Measure Idle CO 0.3 (Propane Enrichment Test)

3A Measure Idle CO and Install 0.5 T Connector

Time allowance includes 0.1 hour for Dealer administrative detail associated with this campaign. Parts credit will be based on Dealer net plus 30% to cover parts handling.

SERVICE PROCEDURE

The purpose of this procedure is to reduce idle CO mixture on those vehicles which were incorrectly set at the factory.

CHECKING PROCEDURE

Because of the sealed idle mixture needle, the idle mixture checking procedure requires artificial enrichment by adding propane.

1. Set parking brake and block drive wheels. Important: Warm up engine sufficiently until cooling fan makes at least one turn spontaneously.

2. Connect an accurate tachometer to engine.

3. Disconnect vacuum advance and set timing to specification shown on the Emission Control Information Label. Reconnect vacuum advance.

4. Set idle speed to 750 +/- 20 rpm. (zero propane)

5. Disconnect air cleaner inlet tube.

6. Using tool J-26911, insert hose from propane valve into air cleaner until its tip touches air cleaner element. Propane cartridge must be vertical.

7. With engine idling, slowly open propane control valve while pressing button. Continue to add propane until speed drops due to over-richness. Observe maximum engine speed (enriched speed). If a rich speed drop cannot be obtained, check for empty cartridge or propane system leaks.

8. A vehicle which exhibits maximum idle speed increase more than 30 rpm above that which was set in step 4, conforms to the service idle CO specification. Proceed to step 10. (Do not install Tee.) A vehicle which exhibits a maximum idle speed increase of 30 rpm or less above that set in step 4, does not conform to the service idle CO specification.

INSTALLATION OF TEE (IF REQUIRED)

9. Install tee in HIC (Hot Idle Compensator) circuit as follows: Remove outlet hose from HIC and cut a 2" piece off the HIC end. Remove 3/4" from that section, and install 1 1/4" piece on Tee (Part #52350705). Reinstall on HIC and into HIC hose as illustrated. Note: 3/4" length must be removed so that HIC tube does not touch intake manifold below.

10. Remove propane hose and reinstall air cleaner inlet tube.

11. Read idle rpm and re-adjust it to 750 +/- 50 if it exceeds 800 rpm.

12. Disconnect tachometer and unblock drive wheels.

INSTALLATION OF CAMPAIGN IDENTIFICATION LABEL

Clean surface of radiator upper mounting panel and apply a Campaign Identification Label. Make sure the correct campaign number is inserted on the label. This will indicate that the campaign has been completed.

Dear General Motors Customer:

General Motors of canada has determined that some 1985 and early production 1986 Chevrolet Sprint and Pontiac Firefly vehicles have an incorrect factory setting of the idle mixture, which may cause them to exceed the emission standards stipulated in Transport Canada regulations.

Please contact your GM Dealer to arrange a Service appointment to have the idle mixture inspected, and adjusted if necessary. The labour time required for this process is approximately 30 minutes and will be performed at no cost to you. Please allow the Dealer additional time to process your vehicle.

This letter identifies your vehicle. Presentation of this letter to your Dealer will assist their Service personnel in completing the necessary correction to your vehicle in the shortest possible time.

Further assistance, if required, may be obtained from the General Motors Zone Office nearest you. Your vehicle Owner's Manual provides the location and phone number of each respective Zone Office.

We are sorry to cause you this inconvenience; however, we have taken the action in the interest of your continued satisfaction with our products. Your prompt cooperation would be appreciated.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.