Early C4 ECM

EJSC4

CCCUK Member
I have a European spec C4 Crossfire, manufactured in early 1983 which has ECM fault. Can any one suggest someone in UK who can repair the ECM and prom which is showing a fault. The Euro spec car did not have catalyser or 02 sensor. I obtained an ECM from the US but this gives 02 fault, this car does not have any 02 connectors on the wiring. I have contacted a few repairers in the US but they are not interested. The mechanic doing the job suggests getting a US spec plug for the ECM and fitting the 02 sensor. I would welcome some help on this as the car is not happy with the US ECM and I dont want to go down the route of fitting 02 sensor and finding it still shows a fault and runs a bit rough
 

Chevrolet

CCCUK Member
Hi EJSC4. You have the Jeff Beck car that Tom Falconer at Claremont restored. Presume you bought it from him? Can Tom not help? He does not come on here, but posts on the CCCUK Facebook pages. He still sells/supplies parts, as you may know?
PS Does a picture of your car with Jeff Beck exist? ;)
 

EJSC4

CCCUK Member
Hi Chevrolet. Yes it is the same car, bought it from Tom. He cant suggest a way forward other than the suggestions I have made in my post. Tom did a good job of putting the car back into roadworthy condition but there were many jobs still to do, which I have been doing over the last three years of so. I only have 2 photos of the car, which are both at Jeff,s house in Wadhurst. One is with his collection of Corvettes and hot rods, the other is at his front door. The sad thing is that I had via a friend contacted Jeff late 2022 he asked if I could attend a car day he was organising at his house which was to be sometime in the summer 2023, sadly it was not to be
 

Chevrolet

CCCUK Member
Well, Just had a look on EBay Germany to see if any early Euro spec C4 ECMs for sale on there. There aren't. But this ECM fault find/repair service in Alfreton Derbyshire comes up. Does this help?
 

EJSC4

CCCUK Member
Thanks for your help. Is Ebay Germany, ebay.com? I have contacted the company in Derbyshire, he said he would have a look at it, I am not assured by the reply "have a look" I would have liked something a bit more positive. Not sure which way to go but I would like to get sorted before the spring.
 

teamzr1

Supporting vendor
I have a European spec C4 Crossfire, manufactured in early 1983 which has ECM fault. Can any one suggest someone in UK who can repair the ECM and prom which is showing a fault. The Euro spec car did not have catalyser or 02 sensor. I obtained an ECM from the US but this gives 02 fault, this car does not have any 02 connectors on the wiring. I have contacted a few repairers in the US but they are not interested. The mechanic doing the job suggests getting a US spec plug for the ECM and fitting the 02 sensor. I would welcome some help on this as the car is not happy with the US ECM and I dont want to go down the route of fitting 02 sensor and finding it still shows a fault and runs a bit rough

Does your Corvette use 1982 electronics or 1984 MY ?
 

Chevrolet

CCCUK Member
Thanks for your help. Is Ebay Germany, ebay.com? I have contacted the company in Derbyshire, he said he would have a look at it, I am not assured by the reply "have a look" I would have liked something a bit more positive. Not sure which way to go but I would like to get sorted before the spring.
Ebay Germany is Ebay.de. He advertises on there as well as Ebay UK (above link). As you can see from his address, looks like a one man band working at home? But as you can see, his Ebay feedback is good?
 

EJSC4

CCCUK Member
I might send my original ECM to him and see what he says. When I spoke to him it was later model Corvettes he could do. Many thanks
 

teamzr1

Supporting vendor
Does not mean the GM was only for the crossfire, being as you stated an "Early 84" GM had a habit for first gen of a new model to use both older and newer parts
Be easy to answer is post the VIN # so we can see how GM spec'd for that year

The vendor I posted above has 4 ECMs for 1984 C4, suggest you go there and contact them to see which would be for Europe
but I am not sure if there was a Europe only ECM but rather a Europe only E-prom what the calibration is stored and in that is where they could turn off functions like the O2

Sane vendor has GM E-prom for the 1984 so also ask which one is for Europe

 

Chevrolet

CCCUK Member
I am fairly sure no 82 model C3 with crossfire eng were made to euro spec, so I guess the 84 euro spec is different
You are probably right. Have never seen a C3 advertised as a "Euro or UK spec" car. No mention of that in Tom Falconers 1983 Osprey book on 1968-82 C3s either.
 

teamzr1

Supporting vendor
Worth a try to open ECM up, check and reflow solder joints and look for any hot spots on components
Clean both male pins of e-Prom, I/C socket and male & female pins of ECM and wire loom pins
 

EJSC4

CCCUK Member
Thanks for all your suggestions. I am not sure if the US and Euro ECM are the same, when I compared the original to the one I obtained from US they have different numbers. I am pretty sure if I could get a prom suitable for the Euro cars it would work with the US ECM. I will try the company you suggested O,Reilly Auto Parts
 

teamzr1

Supporting vendor
VIN Number 1G1AY0780E5108713
Sorry I forgot to show this
Description
Position
Raw Data
Decoded Data
Region:​
1​
1​
North America​
Country:​
1-2​
1G​
U.S.A.​
Manufacturer:​
2-3​
G1​
Chevrolet​
Model Specific:​
4-8​
AY078​
Unknown​
Check Digit:​
9​
0​
Valid​
Year:​
10​
E​
1984​
Assembly Plant:​
11​
5​
5​
Serial Number:​
12-17​
108713​
108713​

Nothing in the car's history shows as for Europe, but maybe just did not keep stats for outside USA

Vehicle Specifications​


year1984makeChevrolet
modelCorvettetrimBase
styleHatchbacktypeHatchback
sizecategorySports Car
made_inUnited Statesmade_in_cityBOWLING GREEN
doors2-Doorfuel_typeRegular
fuel_capacitycity_mileage
highway_mileageengine5.7-L V-8 OHV 16V
engine_size5.7engine_size_units
engine_cylinders8transmission
transmission_typetransmission_speeds
drivetrainRear-Wheel Driveanti_brake_system
steering_typecurb_weight
gross_vehicle_weight_ratingoverall_height
overall_lengthoverall_width
wheelbase_lengthstandard_seating
invoice_pricedelivery_charges

Recalls & Defects​


Recall Subject: Seat Belts:front:anchorage
Report Receipt Date: 09/04/1991
NHTSA Campaign: 91v143000
Summary
Under certain vehicle operations and occupant usage conditions, the safety belts can lock up or jam in the safety belt retractor.
Consequence
If lockup occurs, it is impossible to pull the belt out of the retractor. The occupant of a seat with an unusable safety belt is subject to increased risk of injury or death in the event of a sudden stop or accident.
Remedy
Replace the safety belts if the lockup occurs.
Notes
System: safety belts. Vehicle description: passenger cars.

Recall Subject: Vehicle Speed Control
Report Receipt Date: 03/19/1985
NHTSA Campaign: 85v029000
Summary
The cruise control vacuum solenoid valves may malfunction at any time the engine is running, and the cruise control is engaged and cause unexpected engine acceleration. Consequence of defect: loss of accelerator control could result in a vehicle crash without prior warning.
Remedy
Install and relocate a new cruise control servo assembly.
Notes
Vehicle description: passenger cars equipped with rpo k34 cruise control. System: cruise control.

Recall Subject: Power Train:drive line: differential Unit
Report Receipt Date: 10/01/1985
NHTSA Campaign: 85v118000
Summary
Cars may lose the wire snap rings that hold the differential cross shaft in position in the rear axle differential case assembly, allowing the shaft to move. Consequence of defect: the cross shaft movement could cause the shaft to contact the carrier or pinion teeth, possibly locking up the rear wheels and result in a crash without prior warning.
Remedy
Install a rear axle differential cross shaft retaining kit.
Notes
System: rear axle. Vehicle description: passenger cars with 3.07 axle and f41 suspension.

Recall Subject: Electrical System:12v/24v/48v Battery:cables
Report Receipt Date: 08/25/1983
NHTSA Campaign: 83v081000
Summary
The insulation of the battery cable, because of its position, rubs against some of the engine wiring components. once the insulation is worn through, the battery could rapidly discharge.
Remedy
The dealer will install a new engine harness retainer bracket, protective conduit, cable clips, a cable tie strap and will reposition the terminals on the ground stud on all involved vehicles.
Notes
Vehicle description: passenger vehicles.system: electrical; battery cable insulation. Consequences of defect: the headlights would cease to function, due to loss of battery power; driving at night, in fog or other severe weather conditions could result in an accident.

Recall Subject: Service Brakes, Hydraulic:foundation Components:disc:caliper
Report Receipt Date: 07/07/1983
NHTSA Campaign: 83v064000
Summary
Attaching bolts were mistakenly coated with a slippery material during production. This material will act as a lubricant and bolts may loosen and eventually fall off.
Remedy
Dealer will install new caliper bracket bolts free of charge.
Notes
Vehicle description: passenger vehicles.system: service brakes; front brake caliper bracket to steering knuckle attaching bolt. Consequences of defect: the front brake assembly could become partially separated from the knuckle assembly, causing the wheel to lock. Loss of vehicle control without prior warning and an accident could result.

Recall Subject: Equipment
Report Receipt Date: 10/24/2007
NHTSA Campaign: 07e088000
Summary
Certain Honeywell fram racing brand hp4 and hp8 oil filters that were manufactured from May 25, 2006, through September 14, 2007, and sold for use as replacement equipment for vehicles list above. The affected filters are marked with a date code a61451 through a72571 sequentially. The date code and part number appear on the filter housing. fram racing hp4 and hp8 oil filters not bearing a date code in this range are not affected by this recall. The gasket of the oil filter becomes more pliable under high temperatures and pressures.
Consequence
This condition may cause inadequate sealing and loss of engine oil, possibly resulting in a fire.
Remedy
Honeywell will replace the affected oil filters free of charge. The recall began during November 2007. Owners can contact fram customer service toll-free at 1-800-890-2075.

Market Value​


Below Market Price$6542.21
Average Market Price$8866.65
Above Market Price$11191.09
 

EJSC4

CCCUK Member
The factory build sheet shows many differences to US spec. Leaded fuel, Glass, side indicators, door mirrors, seat belts, radio , front side lights, front indicators, rear lights, rear indicators, rear reflectors, instrument display.
I am finding help or assistance from US companies difficult and virtually impossible.
 

teamzr1

Supporting vendor
I have attached below the full GM engineering specs in PDF format for the design and build for 1984 C4, about 100 pages

Download and save as it has all the design specs for 1984 Corvette
As you mentioned and all I see different is to engine is supported leaded gas

I would not think they would have a different ECM just for that, as the changes for fuel itself would be in the Calibration in the E-prom
Smog items like CATs or O2 sensors would also be just changes to the calibration

If anything, I would assume many years ago that 84 Vette switched to unleaded gas and best case they then switched to harden valves for
unleaded
 

Attachments

  • 1984-Chevrolet-Corvette.pdf
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