Truck stutters

[Slo_Ride 5,000+ posts]

my honest opinion is that something is wired incorrectly. my car would do the same, even shut off at full tilt with the stock alt. you should have enough electo, but the distributor is cutting out from lack of juice. engine light on? last tune up?

 

[voltagexdt 10+ year member]

actually, alternator feeds its field from the stator output after start-up, fyi.......i noticed that you said there were a bunch of 8awg grounds for a 400a system. i believe that is your problem right there. the ground strap from the back of the left head to the firewall is likely toasted by now. at the least, you should have 3 runs of 4awg from the engine to the firewall, or equivalent in other wire size. under 10.5v and your fuel injectors shut off, and ignitor power is weak for the coil. on top of that, you may have damaged the ground runs to the ecu and body, hopefully not internally in the ecu, if this is the case. these trucks can actually run real nice, and be especially good to drive as a manual. only thing i don't really like is the decay rate and small/slow response of the iac valve. normally, if they do give you a problem, you just clean them out with throttle body cleaner and they work like new...... same goes for all of them between then and now. the tps is common to need replacement, and the ignitor around the same time as the fuel pump (100-150k) only real reason to put a carb on it is if you have no means to tune the ecu for whatever engine work you do....... even then, that comes down to lack of know-how, as a tunercat, or efilive/similar tuner is cheaper than a gen2 intake and carb, not to mention you would want to throw a stand-alone ignition in there, like a hei, or aftermarket, as the stock timing advance is done via ecu...... i digress....

long story short: upgrade your engine grounding, and complete the system as a single system, at least in the grounding of everything, and i would suggest you do a pinout from the ecu to grounds/ignitor/block. good luck.

Ok I'm all over doing that tomorrow.

Am confused about "single line system"

Lastly for advice where shall I make new ground points. Example from engine doo hicky to ground

As well should all ground points be same point then to different spots on engine?

Thank u.

 

[voltagexdt 10+ year member]

my honest opinion is that something is wired incorrectly. my car would do the same, even shut off at full tilt with the stock alt. you should have enough electo, but the distributor is cutting out from lack of juice. engine light on? last tune up?

Obd1 so no light.

 

[Slo_Ride 5,000+ posts]

Obd1 so no light.

91 chevy, yes has light. hope you figure it out. i better leave this one alone.

 

[voltagexdt 10+ year member]

91 chevy, yes has light. hope you figure it out. i better leave this one alone.

Right based on obd1 which means light is only on while something is wrong and shuts off when nothing is found to be wrong or problem is fixed. No stored codes as there is no data storage of codes in obd1.

So. Obd1. No light.

 

[Slo_Ride 5,000+ posts]

Right based on obd1 which means light is only on while something is wrong and shuts off when nothing is found to be wrong or problem is fixed. No stored codes as there is no data storage of codes in obd1.
So. Obd1. No light.

dude reading the codes on your vehicle is beyond simple. a blind minkey could do it. dont try to pretend like you have a clue what you're talking about. hopefully you didnt install everything yourself cause it'll cost twice as much to fix if you did. put your truck in the shop and let someone who knows what they are doing fix it. no light. your a dumbass. bottom line is your rigged up crap has screwed up the electrical system of your vehicle and needs to be redone by someone who knows what they are doing.

 

[voltagexdt 10+ year member]

dude reading the codes on your vehicle is beyond simple. a blind minkey could do it. dont try to pretend like you have a clue what you're talking about. hopefully you didnt install everything yourself cause it'll cost twice as much to fix if you did. put your truck in the shop and let someone who knows what they are doing fix it. no light. your a dumbass. bottom line is your rigged up crap has screwed up the electrical system of your vehicle and needs to be redone by someone who knows what they are doing.

It's unfortunate there's always a ******* in every forum. And apparently your this threads *******. Hey google obd1. I'll let google explain it to you since you know everything. Furthuremore I don't know you but from your posts I can almost certainly install circles around you and have proof of it. From solid plexiglass boxes to 2 state SPL trophies of #1 SPL record and sq record. Also featured in 2 magazines. So please admit when you know nothing of what you post about. Sit back and let the grown folk talk. As I came to this forum for knowledgable advice. Not a ******* who knows nothing about how obd1 codes work and then gets pissy and throws a tantrum on a forum with insults.

I'm sure you will respond with more dumb and non productive banter but I have said what I needed to and made my point. I'll wait for the true car audio techs to respond with helpful thoughts and ideas

But thanks for showing your *** and letting me school you a bit.

Enjoy your night while posting your next slew of insults.

A quick hint about obd1. You count the flashes lol

 

[akheathen Premium Member]

okay, you are both right, and both getting wound up and inferring/commenting above what's being stated...... i would do the beefy runs of ground in the stock location from the back of the head to the stud on the firewall. this gets the engine grounding to the same panel as the floor ground and the battery in the back. i assume the 300a alt has a case ground lug, so i would think about putting a ground from that to the same as the rear of the head, and definitely to the front battery along side the power cable, or alternately ground the front battery to the firewall as well as the alt. basically, you don't want any resistance between any of the alt/battery/amp grounds. if you want to keep the truck battery/alt separate from the system alt/batteries, that is fine, just do it on the positive side, and i would also use the ign. wire that you likely split off from the stock alt to trigger a relay on to have the second alt sense it's own battery power. i, personally, like to keep it as one power system, unless i were to do a 16v system, even then i'd probably just power the body feed from a tractor regulator..

 

[voltagexdt 10+ year member]

okay, you are both right, and both getting wound up and inferring/commenting above what's being stated...... i would do the beefy runs of ground in the stock location from the back of the head to the stud on the firewall. this gets the engine grounding to the same panel as the floor ground and the battery in the back. i assume the 300a alt has a case ground lug, so i would think about putting a ground from that to the same as the rear of the head, and definitely to the front battery along side the power cable, or alternately ground the front battery to the firewall as well as the alt. basically, you don't want any resistance between any of the alt/battery/amp grounds. if you want to keep the truck battery/alt separate from the system alt/batteries, that is fine, just do it on the positive side, and i would also use the ign. wire that you likely split off from the stock alt to trigger a relay on to have the second alt sense it's own battery power. i, personally, like to keep it as one power system, unless i were to do a 16v system, even then i'd probably just power the body feed from a tractor regulator..

Ah see some kick *** advice.

I'll do this today. I hadn't thought of the relay. Was going to diode the **** ign wire.

But way better idea.

I'll report back once this is done see how she drives

Thanks bud

 

[undone1 10+ year member]

Right based on obd1 which means light is only on while something is wrong and shuts off when nothing is found to be wrong or problem is fixed. No stored codes as there is no data storage of codes in obd1.
So. Obd1. No light.

actually it will store the code w/o the ses/ces light being on all the time....somes codes do,some don't

welcome to the wonderful world of gm tbi....one finicky little fuel injection..

grounds... 1/0 at least...

engine to frame

battery to frame

frame to body

doing this and multiple battery setup only helped the situation,still pulls down at full tilt..

don't think the tbi system can respond fast enough to being loaded that quickly..

 

[voltagexdt 10+ year member]

actually it will store the code w/o the ses/ces light being on all the time....somes codes do,some don't
welcome to the wonderful world of gm tbi....one finicky little fuel injection..

grounds... 1/0 at least...

engine to frame

battery to frame

frame to body

doing this and multiple battery setup only helped the situation,still pulls down at full tilt..

don't think the tbi system can respond fast enough to being loaded that quickly..

Doing the grounds and relay now.

I want to add a bit more about why I said what I did about obd1 Maybe help slo not say such dumb things obd1 systems can fix themselves with needed to be flashed for code erasal.

However in my situation the truck has the problem for a split second as the bass hits and is fixed as fast when the bass stops. Not long enough to throw a cel.

 

[undone1 10+ year member]

come to think of it,I don't remember seeing any tbi equipped cars/trucks with any significant system that didn't drop rpms during bass tones ( at idle ),at least to some degree...

 

[voltagexdt 10+ year member]

Ok did a major ground upgrade and checked ground resistance

Test and all is good I think. Haven't driven very far will in a few minutes.

But need to ask a question. My oem analog volt gauge sits at 14 when truck is off but pegs passed 19 running. However my dual Dakota gauges one for front a one for rear show 15.3.

Is the relay a cause of this. Should I be worried?

 

[akheathen Premium Member]

sounds like a bad gauge. should not be over 13 at rest. the voltage pulls from the ign, switch/fuse pannel, which also should feed the alt bulb that grounds to the alt your other gauge should be reading correct..... this isn't a new issue, is it? oh, and i never use the frame , unless you are trying to run power to the bed. the firewall is welded to the floor panel, which is welded to the rear pannel and pillars. it makes for a better ground than jumping to-from the frame a couple times. the fender/inner feder/wheel well are all bolted, so i wouldn't suggest those.

 

[voltagexdt 10+ year member]

We'll here's what I did. Using 0ga

From alt to frame

From battery to frame

From engine to frame

From frame to firewall

From engine to firewall

Add relay to alt ignition

Problem after a year is GONE. GONE GONE.

hell ya.

I thought the grounds I provided a while àgo where sufficient but obviously I was wrong

Thanks guys for the advice and help.