viper 791xv won’t crank long enough

If it isn't broken, don't fix it.....

This is a 1999 F250 Super Duty Diesel. My issue is the Remote start doesn't crank long enough to start. a Powerstroke has a prolonged crank before it builds enough top oil pressure to fire the injectors. It retries, and usually starts on the 3rd attempt. It never did this before. It would crank until it fired.

I installed this system over 6 years ago. It has always worked flawlessly. I recently did some upgrades to take advantage of some of the features available that I didn't incorporate during the initial install. I may have inadvertently changed some of the programed settings. Here's what I've checked, and the settings I've used. I know this is an old system, but thanks for any hints. I don't know what to try next.

Item 3-1 Engine Checking = On.
Item 3-2 Engine Checking = Tach
Item 3-12 Anti-Grind = On. (I also tried Off. No difference).
Item 3-13 Diesel timer = Wait to start

I've also performed the "tach learn" procedure several times. The LED comes right on, so it sees the tach.

Thanks for reading.

It's possible that the problem lies more with the glow plug relay or the glow plugs. I have an 02 7.3L Powerstroke (granted, without a remote start) and it was getting pretty difficult to start when it was cold (required much more cranking that it had in the past) until I replaced the glow plugs and the glow plug relay. Actually, it's possible that since you are in Cali that you have a California emissions model that has a Glow Plug Control Module (GPCM) instead of the relay, but apparently they still go bad quite often when they get old.

Thank you for the feedback. I appreciate it.

I too have thought that it may be glow plug related, and is a "hard-start" problem not directly related to the remote start crank-time.

This truck was purchased new in Colorado by a very close friend, (so I know its history) and then by myself in March of this year. It's a Federal Emissions truck (I didn't know there was a difference in glow plug management, now I do, and will investigate this)and there was about $1,500 of work done a year and <7,500 miles ago to solve a "hard start" that included replacing the glow plugs and the relay.

I'm not sure what it is, but again, I appreciate the input. Thanks for the interest.

Where are you getting the tach signal from? Have you always used the tach input? How long is it cranking before it shuts off?

You may want to try to learn tach at a slightly higher then idle RPM. This trick works on some vehicles.

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Kevin Pierson

KPierson wrote:

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Where are you getting the tach signal from? Have you always used the tach input? How long is it cranking before it shuts off?

You may want to try to learn tach at a slightly higher then idle RPM. This trick works on some vehicles.

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Thank you for the suggestions.

I don't remember the wire color, but I'm using the tach wire in the main harness behind the brake pedal. None of this was disturbed during the recent work.
Yes, I've always used the tach input, and wait to start. It cranks for appx a second, then stops. Waits about 20 seconds and tries again. If I start it with the key, it has to crank about 2 seconds to start. This is slightly longer than typical for this truck. Hence why it may be a truck problem, not a remote start problem.

One of the quirks I recognized when I was re-learning the tach yesterday, is that if I push the button, turn on the key, wait for the "wait to start" to time out, then crank it the 2 seconds required to get it running very, very close to 5 seconds or over has elapsed[/I}. If the 5-second learn period begins when the key is turned on, the engine may still be stopped when it "reads" the tach signal.

I was thinking of trying this for a re-learn to avoid timing out on the 5 seconds before the engine is running:

Start engine
Disconnect ribbon cable from satellite relay cluster (gets ign input from this cable).
Raise idle speed slightly with foot.
Push button.
Plug in ribbon cable within 5 seconds, and see if LED comes on.

Think it will work? Or any other ideas how to beat the 5 second clock on the tach-learn if it takes 5 seconds or more to get it started after key-on?

Thanks.