My 1996 Discovery fails to restart after it has warmed up. I've had the truck about 4 weeks and the problem has occurred twice in the last 10 days as the weather has warmed up. The guy I bought the truck from told me about the issue. He thought he'd fixed it. But wasn't sure. He said, if it occurred, to wait 20-30 minutes and it would restart. He also showed me how to bleed the fuel rail to clear air out of the system to get the vehicle to restart quicker. The first time the truck wouldn't start I'd been driving it around for about an hour or so. Since I was in a national forest, I just locked the truck and went to scout a trout stream. After about 2 hours, I returned to the truck and she fired right up. The second time, I had driven the truck across town, maybe a 15 minute drive, to a get something and when I came back to the truck, 5-10 minutes, it would not start. Between bleeding the fuel rail twice and waiting about 15-20, I was able to get the truck to start. I've search the board and identified several possible causes from other posts:

1) Coolant Temperature Sensor - ECU
2) Fuel Temperature Sensor
3) Crank Position Sensor
4) Fuel Pressure Regulator
5) Fuel Pump
6) Fuel Injector

As I understand it, 1) & 2) should cause the check engine light, little light under speedometer, to come on which has not occurred. I believe 3) was replaced by the prior owner. So, that leaves 4-6. I'm fairly certain that I have a leaking fuel injector (6) and I have noticed that the low fuel light will come on intermittently when the tank is far from being empty. Questions a) Should all the fuel injectors be replaced together or is it ok/standard procedure to just fix those that are leaking? b) Does the low fuel light issue indicate the fuel pump is going bad or is it more likely a wiring issue ? c) Any suggestions as to the order in which the above are fixed/replaced to address the issue.

The truck is a 1996 Discovery, 5 speed manual, 140K miles, runs well otherwise, no hesitation when accelerating, seems to have plenty of power. Also, the prior owner had replaced the coil pack, spark plug wires and plugs.

Any help will be greatly appreciated.

 

When it refuses to start pour water on the crank sensor and see if it starts, that should be heat shielded along with the wireing


Injectors just upgrade the set to the orange Volvo, u pull yard 5 cylinder engine, a search will show the part number

That light I would start with pulling the cargo carpet and remove the access plate , see how that looks , dielectric grease the connectors everywhere on the truck, there is also a harness plug around drivers rear wheel well on frame

 

if you have access to a fuel pressure gauge that you can leave mounted to the fuel rail.....you could drive the truck until it;s "warmed up" and then let it sit for the time....and the fuel pressure shouldn't go down appreciably in that short a time . the pressure should be in the low to mid 30's psi

 

Warm restart issue is the coolant temp sensor for the ECM. They're cheap, buy another and test. Don't rely on the Check Engine Light or the ECM to light it. If that doesn't bring it around then the fuel temp sensor is next. What's happening is either the coolant sensor is reporting a cold engine when it's not and flooding it or the fuel temp sensor isn't allowing air bubbles from hot fuel to purge (injectors wide open) which vapor locks the fuel line. Good luck, report back.

 

Need to find out if it is electrical (spark) or fuel related. When it won't start, see if there is fuel at the fuel rail. I found mine (which did the same thing) ended up being the inertia switch on the firewall (under the hood) the contacts were oxidized and black from arcing. I stripped the wires back, tied them together and drove home. I fixed it right once I got home. hasn't acted up in 3 years now.


I was able to listen for the fuel pump to run when I first turned the key. It only runs for a short time and if the motor doesn't start, it shuts off.

 

Checked the folder of maintenance items the PO gave me. Found an invoice from AB for the fuel temperature sensor from the fall of 2015. So, I figure he installed that sensor. He had a very nice garage set-up with an air compressor and pneumatic tools. Kinda clued me in that I needed to do some work on my gravel driveway and carport. Also, need to move the John Deere from the carport to a storage shed. Both will earn brownie points with the wife and give me some room to work on the truck. Ordered the ECM coolant temperature sensor with brass o-ring from AB today. Hope to install it this weekend. That may be overly optimistic since I selected the USPS for delivery. As to not getting fuel to the rail, the PO showed me how to bleed the fuel rail using, what I assume is, the port for the fuel pressure gauge. When the truck wouldn't start the 2nd time, I tried the port and got a strong stream of fuel. So, I'm making the assumption that fuel is getting to the rail at least. After installing the ECM coolant temperature sensor and relocating the John Deere, I'll move onto testing the fuel pressure, ... Appreciate all the held. I'll post the results of the coolant sensor install.

 

U need a scanner, like ultragauge, auto zone sells one also, you can mount it to display sensor readings like temp, do not trust that gauge

Try lucky 8 next time ab is the most expensive usually

 

ihscouts is the man, I would start where he says to start.

And you need to systematically go through and eliminate each possible cause, hopefully not by throwing new parts at it at random; that gets expensive real quick.

I am not as knowledgeable as some on this site, so I can only relate my own experience. I had a hot start problem, similar in nature, let it cool down for half an hour and it would run fine.

I replaced the fuel pump, which was weak, and crank position sensor in the same wrenching session, and the problem went away.

Your mileage may vary.

 

Drove the truck to Johnson City for a four hour meeting. Left about 4 pm and the truck wouldn't start. Bleed the fuel rail like the PO suggested. Reset the inertia switch as Jimvm57 suggested. Poured water on the CPS, i think, as Tom R suggested. Fiddled with this an that. Nothing seemed to work. Finally, in frustration, I turned on the AC blower fan and then pushed all the buttons on the dash. Turned the key and she fired right up. Sat in the truck and pondered the last twenty frustrating minutes. Decided this really wasn't a "warm start" scenario as the truck had been sitting for 4 hours and perhaps the ECM coolant temperature sensor isn't the problem. Maybe it's electrical. But couldn't come up with a plausible electrical problem that pushing the dash buttons would have resolved. Pondered some more and decided the warm start issue is one indicator but not the only indicator that the ECM coolant temp sensor is going bad. So replacing it still makes sense. Besides, it's already in the mail from AB. Went to roll up the windows and sure enough the driver's side rear window either came off the track or the regulator broke. Upside to that fail is I know it's an easy fix.

 

Ordered an ultra gauge,wireless version, which will pair up with my iphone by blue tooth. I'll provide some data off that puppy after I get it figured out and up and running.