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Lift pump issue?

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I have an airtex lift pump and it has been great. I changed my fuel filter last night and went to bump the starter and got nothing. My pump in the past has always run after bumping the starter. I got the truck running and the fuel pressure was fine: 18 PSI idle, 14 PSI cruise, never below 12PSI. I have stock fuel lines so it is going to drop a little more than bigger fuel lines.

 

Any thoughts as to why the fuel pump didn't run when I bumped the starter? Would it be some sort of relay issue, computer issue, or just fuel pump issue? :shrug:

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Do you have the lift pump running off of the ECM, or do you have the ECM running to a relay and the power for the pump coming from the battery?

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Since it is a stock replacement, I think it is running just like the stock setup. However, I'm not 100% positive. It was in the truck when I bought it.

Verify where you are getting power from.  does the OEM plug go into a relay or directly to the pump?

Do you have a delayed wait to start light? It could be a sign of a failing ECM. Mine would run sometimes and other times it would be on/off/on/off.

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Lately, I haven't seen the wait to start light at all. I assumed it was due to 100*+ weather lol

 

Failing ECM is no good. That's a lot of $$$$ isn't it?

It should ALWAYS flash a wait to start light no matter what the temperature... and yes ECMs are not cheap.

I just cycled mine and the WTS light only stays on briefly. It is one of the first lights that goes off and might be easy to miss. IIRC the WTS issues were the truck not starting until the light went off. I could be wrong though, it has been a while.

For me I had to wait for the light to come on for it to start. Sometimes had to wait 5-7sec. for it to come on but when it came on it always started. Seems like most of the ECM issues I've been seeing lately have been on 99 trucks. Known good used ones show up in the classifieds for $300-500, and should be plug and play if you get the same year and transmission. Don't lose any sleep yet. Try unplugging the ECM, after disconnecting the bat grounds, and slathering the connecter with dielectric grease and plugging it in and out a few times to make sure everything is coated ( not my idea but it works ). It's easier if you take the intake horn off. It could be just a loose screw on the connector or dirty connection. Theres also a thread on here from a guy who got his rebuilt with good results for I think around $700. You'll need to look for it because I don't remember the place.

Edited by dave110

For me I had to wait for the light to come on for it to start. Sometimes had to wait 5-7sec. for it to come on but when it came on it always started. Seems like most of the ECM issues I've been seeing lately have been on 99 trucks. Known good used ones show up in the classifieds for $300-500, and should be plug and play if you get the same year and transmission. Don't lose any sleep yet. Try unplugging the ECM, after disconnecting the bat grounds, and slathering the connecter with dielectric grease and plugging it in and out a few times to make sure everything is coated ( not my idea but it works ). It's easier if you take the intake horn off. It could be just a loose screw on the connector or dirty connection. Theres also a thread on here from a guy who got his rebuilt with good results for I think around $700. You'll need to look for it because I don't remember the place.

I did a little research this afternoon and I found that what you experienced was what I was thinking about. Delayed light and no start until it came on.

 

Even though this is leaning toward a new ECM, I think i would start checking and cleaning any connectors just to be sure. ECM's are quite pricey. i lost my ECM several years ago but with little or no symptoms. Ran a little funny one evening and the next day going to work it just crapped. it would start and idle but was undriveable. 

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Yikes! So, my WTS light does not come on, but out of habit I wait for a bit before starting the truck. It starts fine, runs fine, and fuel pressure is good. I will try cleaning the connections. Where can I buy an EMC if I really do need one?

Is this a good place?: http://dodgepcmdirect.com/productlist.php?make=dodge&model=Ram%20truck&year=1999

Or this one? :https://www.autocomputerexchange.com/catalogsearch/advanced/result?brand=72&model=144&year=56&engine=172&product_type=199&price[from]=&price[to]=&search=

I have seen this symtom before and disconnecting the batteries and letting the ecm reset fixed the issue.

question, is your truck manual? if so you may have a noise electric system, in autos, this will cause funny shift patterns and random TC lockup drop ins and outs.

 

if this was mine, I would disconnect all four battery clamps, clean, inspect and reinstall, re calibrate the apps (this is required any time the power is disconnected) 

and see if that addresses the issue

 

Just my 2cents

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Thanks for the tip! I have an auto trans. I will try to do that this afternoon after work (weather permitting).

Edited by ty_lowcountry

cool, keep us posted,

because these little gremlins these trucks have, I have decided to restore my ole 92 first gen,

at least being straight mechanical , I know an ECM will not leave me on the side of the road :)

and once complete, sell my 99 (install the ole 12v with the manual trans in it LOL)

search this forum for " best option for rebuilt ecm" by imbodie. He had his redone somewhere. But I would try the things listed above first. Also have you checked your alternator for AC voltage? Theres an article on how to do so.

in the meantime you can wire up a relay with a switch in the cab that allows you to provide power to the lift pump.  

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in the meantime you can wire up a relay with a switch in the cab that allows you to provide power to the lift pump.  

 

Since I get good fuel pressure while the truck is running, I'm not sure that is necessary? I guess for fuel filter changes that would be a good idea though! Hopefully I'll have this sorted out before the next fuel filter change :pray:

I would recommend installing a relay that the ECM triggers so that the power being pulled by the pump does not run through the ECM. It's how Fass  has their wiring kit made.

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