trying to solve hard starting condition, new to grand nationals! Any ideas?

cjmatt

Moderator
Joined
Aug 31, 2007
hey evryone, I just picked up an 87 GN, love it so far! One issue I'm having is that it takes a little bit of cranking before it'll start up, probably about 4-5 seconds. I've so far removed the throttle body and cleaned it all out as well as the iac passage, and replaced the plugs and wires. It also is idling very low, about 600-650 rpms I'm guessing. Anyone have any ideas on what I should check/change next?
 
Go to gnttype.org. There is tech information as to base settings and "spring cleaning" stuff.

Good luck.
 
Get a good scan tool, as those readings will help diagnose the problem.
 
Good luck with the car, and I agree with the above post-if you own a TB you should own a scan tool of some type (ScanMaster comes to mind).

Your idle speeds sounds about right, I recall from somewhere 500-550 being the min.

As for 4-5 seconds of crank time-ONE possibility would be a bad fuel pump relay, not powering the fuel pump on initial cranking. After cranking your engine and oil pressure is obtained the fuel pump will run and start car.
 
Another big one is to replace your positive and negative batter cables, if they are originals. Check all of your grounds, as well, and make sure they're in good condition. You want a good solid hit on the starter solinoid to get that sucker fired up. You electrical system is often overlooked.
 
Good luck with the car, and I agree with the above post-if you own a TB you should own a scan tool of some type (ScanMaster comes to mind).

Your idle speeds sounds about right, I recall from somewhere 500-550 being the min.

As for 4-5 seconds of crank time-ONE possibility would be a bad fuel pump relay, not powering the fuel pump on initial cranking. After cranking your engine and oil pressure is obtained the fuel pump will run and start car.
You know, now that you bring it up, im not sure if ive heard it prime yet. Will the hotwire kit and pump fix that?
 
hotwire wont fix it

check the fuel pump relay

if car is functioning normally your fist turn of the key to run position will cause the fuelpump relay to close for about two seconds (the pump should run when closed)

then once started the relay will reactivate once rpm is above 400 rpm

if relay is no good there is a backup fuel pump power which is the oil sender switch at the front passenger side of the timing cover . if you have an aftermarket oil pressure gauge its not uncommon to find the original oil sender switch missing with a vdo electric sender screwwed into its place and the plug for the oe sender just hanging there. The oil sender switch (which im guessing you still have because car starts) will turn on the indash idiot light if oil pressure is below 4psi but it also serves as a secondary power to the fuel pump when oil pressure is above 4psi should the fuel relay go bad (it also helps takes some of the load off the relay )

if your fuel relay on passenger fender went bad the sender switch will allow the pump to run once oil pressure is over 4psi, this may be why you're cranking so long since it needs to get oil pressure before pump runs to build fuel pressure for the injectors


here's a link, lots of other good tech advice on the site
Fuel Pump
 
You have relays on both inner fenders...both sides under the hood. The drivers side is your high speed fan relay, low speed fan relay, and then the delay box, which keeps the fan running after shutdown. The other side has the fuel pump relay, the knock sensor module, and something else...cant recall....
Anyway, pop the connectors off and unbolt the relays from the inner fenders. You'll probably have alot of dried out hardened dielectric grease from 20 years ago. Get a pick and pick it all out, then pour some ronsonol lighter fluid or kerosene in all those sockets, and gradually clean it all out. Id recommend a blow gun, but dont use acetone. Pick all that crap out, and also the stuff on the pins on the relays. Take your time and clean it really well because the end result is worth it. You want shiny clean sockets and pins. Otherwise it'll take alot of current to drive the fuel pump and fan and things will get overloaded, and you'll have major voltage drops...like 9-10 volts at the fuel pump and even less at the fan..I had 8 volts going to the fan when I got my car. The fan was hardly spinning. Try this first, and get a scanmaster YESTERDAY. Dont even think about owning a turbo regal without one. Then you can fire it up, let it reach operating temp, go into closed loop, and then you can post all the numbers it's showing and we can help you much better that way.
 
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