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Discussion Starter · #1 ·
'87 Shelby Daytona
2.2 Turbo II

No codes other than 12 and 55.

Haven't used the car in a long while and have recently got back to doing some work to it. A new problem has popped up where whether sitting at idle, or holding the throttle at any rpm, the engine will just cut out like somebody turned off the ignition.

I've changed out the HEP (it's possible I have two bad ones), I've changed out the MAP (which only made it run WORSE.... I think RockAuto sent me the wrong one) I have wiggled every connection looking for something loose, a bad ground .... everything.

The only things I've never changed on this car were the O2 sensor and the fuel pump. When turning the car on, you can usually hear the fuel pump prime. I'm not 100% certain, but I recall hearing the fuel pump prime longer than 1 second.

Secondly, I have attached a fuel pressure gauge and when the engine stalls, fuel pressure drops.

I'm thinking fuel pump. But before I go tearing in, what do the experts think? Am I on the right path or not?
 

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pull the vacume line off the fuel regulator and give it a sniff
if it smells like gas you need a regulator as it's leaking internally
 

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Discussion Starter · #4 ·
Fuel pressure is good but when the car stalls, the fuel pressure drops now I'm not sure if the pressure is dropping because the engine is stalling or the engine is stalling because the pressure is dropping. When I 'deadhead' the pump, pressure rises accordingly.
 

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Did you read and follow the thread for checking fuel pressure?

Fuel pressure should not drop when the car stalls.
Connect your fuel pressure gauge, start the engine, rail pressure should be reading 45-48 PSI with the vacuum line connected to the FPR, shut the car off, pressure should not drop.
(NOTE...Pressure will drop slowly after engine is shut off, 10, 15, 20 minutes or so)

When you deadhead the pump pressure needs to jump to a minimum of 80 PSI instantly, did it?

NOTE...Do not deadhead the pump with the engine running.
With the key on/engine off manually actuate the ASD Relay, verify static pressure is correct (53-57 PSI) then pinch off the return line.
 

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Discussion Starter · #6 ·
Okay, got some good news.

Fuel Pump: 20 psi at rail initial Key-on Prime
46 psi running, gauge is initially steady but does start to get a bit jittery, when it stumbles the pressure actually goes UP! and when (if) it catches the pressure returns to a steady 46 psi.

HOWEVER, I did find that by jiggling the black connector on my HEP, I can make the engine stall completely. Sometimes even just moving it causes the engine to stumble and/or stall so I'm going to say I think I've found the issue. Bit unusual as I've moved this connector around before and it never made the engine stall before!

Is the black connector the one that controls fuel or ignition?
 

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Black is the crank signal, gray is the fuel sync signal.

If you lose either signal you get the same result, no ASD actuation which equals no power to the + coil, injectors or fuel pump.
 

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Discussion Starter · #8 ·
Well, I finally solved it.... and I'm ashamed to admit it was something really, really simple.
Even though this WAS a brand new coil in 2013.... I guess the rubber boot on the wire was not doing it's job. Look inside that tower. That's a lot of corrosion or damage from arcing. The connector at the end of the wire was not happy either. Regardless, I've swapped in a new MSD Blaster 2 coil; cleaned that wires connector and have put a couple hundred nearly trouble free miles on the car this summer.
I say nearly as it does still occasionally hesitate.... but it's split-second kind of stuff. I guess I have to re-check all my own work. Probably time to do plugs as those were last done in 2015.... might be time for cap and wires, too. Not a lot of mileage on them, but they're getting old. I guess it really is true that letting a car sit is the WORST thing you could ever do.

275749
 

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Glad to hear the problem has been corrected, we have all been there with the problem being right under our nose.

Just an FYI...
The MSD Blaster coils are not the correct Primary Resistance for our cars (MSD Blaster .7 Ohms, Chrysler 1.34 - 1.55 Ohms), you need to add a .7 or .8 Ohm Ballast Resistor to the Coil + Circuit to prevent any future issues.


CHRYSLER OIL FILLED COIL SPECS
SPECS-Ignition Coil 1.jpg
MSD BLASTER SPECS
BrandMSD
Emission Code1
Inductance8 mH
Maximum Voltage45,000 Volts
Peak Current140 mA
Primary Resistance.7 OHMs
Product TypeCoil
Secondary Resistance4.5K OHMs
Spark duration350 uS
Turns Ratio100:1
WarrantyLimited 1 Year Warranty
WeightN/A
UPC085132082025
Part Number8202
 
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