Engine/Transmission (1998.5 - 2002) Grid heater and relay questions

[Steve Robinson]

Along with a hard starting issue after installing a FASS DDRP-02, I have a volt gauge that is very slow reaching 14 volts right after starting. If i turn the headlights on, it takes even longer. I installed new batteries--no help. The tech at the alternator shop checked the alternator output and said it was fine at start and the gauge was just slow. I also notice the "check gauges" light remains on until the voltage gauge begins to climb and will often relight as the grid heater cycles on, at least I think "as the grid heater cycles on"?? I also see that the fuel pressure is very slow to to rise as well during this period, after full voltage is reached (indicted by the gauge) I will have 19-20psi of fuel pressure. So, now I am thinking the grid heater may be be the problem or perhaps one of the two relays going to the grid heater causing too much voltage draw, or sticky relay, or some other issue. The truck has 150k miles, if that makes any difference.

The questions: 1. Anyone with the slow volt gauge problem?

2. Do you have a vendor for a new grid heater and relays?

3. What do these parts normally cost?

4. Should both relays be replaced?

5. Am I headed in the wrong direction with this problem/

advice?

And a big thank you!

 

[Sticks]

Verify your alternator output with a voltmeter at startup.

You can disconnect the Grid Heater relays by pulling the 18ga. wires off the screw terminals (they just slip on) to see if that makes any difference Each one has 2 wires. You only need to pull one, but I can not remember which one (L or R). They are located under the drivers side battery/PDC mounted on the fender.

Loose or worn serpentine belt can cause this as well.

 

[JohnBoy5]

There is also a plug on the passenger side well 2 plugs. take them loose clean and put back. they are right next to the batteries. I am assuming you have a 2nd gen truck as I do not see anything about what truck it is.

 

[Steve Robinson]

Sticks, thanks for the input. I have cleaned the plugs as indicated by JohnBoy5, removed all leads to the grid heater from the relays, cleaned them and still the same result. The belt looks fine. I even disconnected the two wires leading to the grid heater, started the engine but again, no difference. I am baffled. Any other thoughts.
It's a 98. 5 24 valve, by the way.

 

[JohnBoy5]

have you had your batteries load tested? like disconnect them from everything and load test them. sounds like 1 batterie may have a bad cell causing this draw and eventually the alternator is able to over come this because if i am correct its like 120 or 150 amps.

i am baffled at this and am taking it personal now. lol

here is one more test. un hook the fass system from your truck and set a batterie next to the truck and run the pump on that batterie while you start your truck. see how it recovers then. maybe there is a defect in the pump motor...

 

[Steve Robinson]

When this madness began, I also figured the problem was battery related so I bought new ones. It did not help the problem and that is when I took the truck to a generator/alternator shop for a check of the alternator. As I indicated in my original post, the alternator is fine and the tech told me the gauge was just tired and getting slow to react. We are also thinking alike with the lift pump scenario. I changed from the stock lift pump to the DDRP-02 thinking the stock pump was the culprit and was drawing too much voltage. Again, no help with the pump change, the only difference is my truck no longer starts with a touch of the key, I have to crank it a bit but so far, it has started every time. A new development with the FASS pump though is it will not give me the pressure surge at the onset of the ignition as it used to. It did for the first couple of weeks, to more than 15 psi, but now my pressure gauge indicates no pressure surge prior to starting. I don't know if this is a symptom of the voltage draw issue or a sign of a defective pump. The pump seems to work just fine after starting and it makes it's ever-so-slow climb to 18-20 psi. I'm still baffled here and I very much appreciate your input. If you think of something more please let me know.

 

[JohnBoy5]

just a quick question related to the hard to start problem. is you fuel pump running when you try to start the truck?

you might take the truck to the dealer. there is a computer update to correct some of these problems. i just had mine in there. the only bad thing is they put on a speed limiter at 118 mph :-(

i just noticed that you say no pressure when you turn the key. seems like mine was having a problem also before i went and now it does good. one thing i did start doing is turn the key to the on position stop for about 2 seconds then move to the start position. the truck lights off right away like that. other wise i have to crank for a bit.

do you have a DC current clamp or can you get your hands on one? if you can check to see if you have a drain on the system with the key off then check it with the key on and the engine off then start the engine and check again. also with the engine running take a box end wrench and let it hang in front of the alternator pulley being very carefully not to let it get in the belt. if the alternator is working right it will put a strong pull on the wrench.

here is an example of a current clamp incase you are not sure what i am talking about Clamp Meters

 

[fest3er]

If one of the heater relays has stuck 'on', unplugging the control lead won't make a difference. Measure voltage between the intake heater studs (top of the manifold) to ground. If you see any voltage with the key off, engine off, that relay's stuck on. If the intake manifold is warm when you expect it to be cold, a stuck relay is likely the cause.

Search the forum for "Stancor", or just visit my heater relay web page. THe PDF'll have what you need to know to replace the relays with solid aftermarket relays. Mine still behave like new after 8. 5 years.

Of course, a bad temp sensor might be confusing the PCM into thinking it's below zero outside. But the 'low voltage' condition would only last until you reach 18MPH or so if the PCM is truly controlling the heaters.

 

[Bob Cochran]

Here is an off the wall thought. Could you have to much pressure on initial start? I think I might have read you said zero pressure. Both will cause hard starting. I seen you have had the alternator professionally test so I will not be like others and keep telling you of ways to test the alternator!!!

 

[Sticks]

Along with a hard starting issue after installing a FASS DDRP-02, I have a volt gauge that is very slow reaching 14 volts right after starting. If i turn the headlights on, it takes even longer. I installed new batteries--no help. The tech at the alternator shop checked the alternator output and said it was fine at start and the gauge was just slow. I also notice the "check gauges" light remains on until the voltage gauge begins to climb and will often relight as the grid heater cycles on, at least I think "as the grid heater cycles on"?? I also see that the fuel pressure is very slow to to rise as well during this period, after full voltage is reached (indicted by the gauge) I will have 19-20psi of fuel pressure. So, now I am thinking the grid heater may be be the problem or perhaps one of the two relays going to the grid heater causing too much voltage draw, or sticky relay, or some other issue. The truck has 150k miles, if that makes any difference.

The questions: 1. Anyone with the slow volt gauge problem?

2. Do you have a vendor for a new grid heater and relays?

3. What do these parts normally cost?

4. Should both relays be replaced?

5. Am I headed in the wrong direction with this problem/

advice?

And a big thank you!

Lets go back to the most recent change, as JohnBoy5 pointed out. If the truck started and ran fine, including normal voltage before the FASS, and now has a hard start and power issues, I'd be looking at the install.



FASS relay, wiring, connections, ect.

 

[Steve Robinson]

Sticks, thanks for the thought and I am sorry I mixed the two issues (FASS and voltage) together. This voltage thing has been going on for some time before I installed the DDRP. Grasping at straws, I keep changing parts in hope of fixing the problem through my ignorant logic. Thank you for your input.

 

[Steve Robinson]

Bill, I have tried two different gauges and sending units but the westach gauges consistently show no (little, maybe 1-1. 5 psi) pressure surge just prior to start. I will be running the tests Fest3er and JonBoy5 have suggested today and with luck I'll have fixed the voltage problem or at least gotten closer. As far as the FASS issue, Monday I'll call one of the FASS reps with the hope he can give me a clue as to where the missing pre-start surge has gone. Thank you for taking the time to help me with this, I appreciate it much.

 

[Steve Robinson]

JohnBoy5, I checked to see if the DDRP was running with the key on and engine off. There is no indication that it is running; there is no vibration nor is there any sound that I can detect with my poorly functioning ears. Is there actually a computer upgrade for my truck or were you just using that as a set-up for your 118mph joke? My truck has not visited a dealership in years, Thanks again.

 

[Steve Robinson]

Fest3er, I checked the voltage between the studs on the grid heater as you suggested with engine off and key off. There is no voltage in this condition between either stud and ground. I also tested for voltage on the hot side of the relays and both show 12 volts, so, I would conclude the relays are open and functioning as they should. Have I missed something or would you come to the same conclusion? I will check out the solid relays you have mentioned, but at this point, it doesn't seem like the relays are the culprits, wouldn't you say?

 

[Sticks]

The FASS (if installed correctly) is controlled by the ECM, and gets it's power from a relay connected to battery positive. READ - The ECM signals to turn the pump on, sends a 12v signal through the OEM lift pump harness into the FASS harness, closing a relay, which sends the 12v power from the battery to the pump. A bad connection anywhere along the lines could cause your FASS not to turn on or not run properly. Excessive corrosion or poor connections will cause a variety of problems as well.

 

[JohnBoy5]

JohnBoy5, I checked to see if the DDRP was running with the key on and engine off. There is no indication that it is running; there is no vibration nor is there any sound that I can detect with my poorly functioning ears. Is there actually a computer upgrade for my truck or were you just using that as a set-up for your 118mph joke? My truck has not visited a dealership in years, Thanks again.

There really is an upgrade. If its been a while i would get all 3 computers upgraded. Part of the upgrade is 118 mph will be you top speed and they can not disable it. Some of the upgrades are lift pump and vp44 upgrades. If you need more info pm me. I am on my phone now and its hard to type

 

[JohnBoy5]

any word on any of this?

 

[Beast2B]

Anyone local member with a Smarty can update your truck to the latest factory software (as long as the Smarty is up to date). The Smarty keeps the factory load in its memory, not the particular truck. So, if someone loads a Smarty load on your truck and then returns it to stock it will have the latest factory load. Also, I can change the speed limiter to anything I want with my Smarty!

 

[JohnBoy5]

Anyone local member with a Smarty can update your truck to the latest factory software (as long as the Smarty is up to date). The Smarty keeps the factory load in its memory, not the particular truck. So, if someone loads a Smarty load on your truck and then returns it to stock it will have the latest factory load. Also, I can change the speed limiter to anything I want with my Smarty!

that will only update the ECM not the trans computer VP44 or chassis computer... these trucks have a lot of computers on them.