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3800 Weak starting after sittng overnight by zmcdonal
Started on: 10-30-2014 05:42 PM
Replies: 4 (159 views)
Last post by: Darth Fiero on 10-31-2014 01:21 PM
zmcdonal
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Report this Post10-30-2014 05:42 PM Click Here to See the Profile for zmcdonalSend a Private Message to zmcdonalEdit/Delete MessageReply w/QuoteDirect Link to This Post
My 3800 will crank really slowly, and take a few tries to start if it has sat for a most of the day or overnight. If it has been run in the past couple hours it fires right up with no issues. It has a brand new battery in it already. I thought maybe the starter was weak and on it's way out. After reading a bunch of threads on here I read that my new low mileage 2.8 starter should bolt up and work with not problem. I swapped it out it bolted up with no issues. However the starter from the 2.8 was physically larger, so the + wire coming from my battery was just barely too short to reach the post.The car has a front mount battery so I went and bought 2 gauge welding cable and ran a new lead to the starter. When I tried to start the car, the starter sounded weak and made a grinding sound. I installed it with no shims, just like the original 3800 starter was. So I took the shim that came off the 2.8 starter and installed that thinking maybe that was my issue, same result.

Side by side comparison of the two starters




I then took the old original 3800 starter down to autozone and they tested it twice and it passed both times. Any ideas what could be causing my problem? When it takes a few tries to start it drains enough power to reset the radio.

[This message has been edited by zmcdonal (edited 10-30-2014).]

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nosrac
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Report this Post10-30-2014 06:33 PM Click Here to See the Profile for nosracSend a Private Message to nosracEdit/Delete MessageReply w/QuoteDirect Link to This Post
Where are your grounds? You mentioned front mount battery.
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zmcdonal
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Report this Post10-30-2014 07:59 PM Click Here to See the Profile for zmcdonalSend a Private Message to zmcdonalEdit/Delete MessageReply w/QuoteDirect Link to This Post
This is how the ground is done up front at the battery
This images is larger than 153600 bytes. Click to view.

Which I've read it's a better idea to run a ground cable all the way back to the engine from up front, but this is how it was done when I got it and it seemed to be working.. I am not sure how the grounds are done on the motor, I will have to check into that. I was thinking that could be a potential problem.
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nosrac
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Report this Post10-31-2014 01:57 AM Click Here to See the Profile for nosracSend a Private Message to nosracEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zmcdonal:

This is how the ground is done up front at the battery
This images is larger than 153600 bytes. Click to view.

Which I've read it's a better idea to run a ground cable all the way back to the engine from up front, but this is how it was done when I got it and it seemed to be working.. I am not sure how the grounds are done on the motor, I will have to check into that. I was thinking that could be a potential problem.


IMO, It is better to have 3 Main grounds. Battery to Engine block, Battery to Chasis, Chasis to Engine Block.
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Darth Fiero
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Report this Post10-31-2014 01:21 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
When relocating the battery up-front, here is how I set up my grounds:

I run a large (2 or 4ga) ground cable from the battery NEG terminal to the front spaceframe of the car's body outside of the front trunk compartment. I usually connect it to a hole I drill near where the factory sway bar bolts up to the subframe rail in the 84-87 cars. DO NOT connect the ground cable to the front suspension K-member as this piece isn't part of the vehicle's spaceframe (and there's a chance it could not be grounded very well to the vehicle's spaceframe because it is bolted onto painted surfaces from the factory).

I also run a smaller (8 or 10ga) ground cable from the battery NEG terminal to the sheet metal in the front trunk compartment (usually one of the studs for the jack storage bracket).

Back at the engine, I connect a 2 or 4ga ground cable from the block to one of the thicker metal plates that are welded to the Fiero body that the front of the engine cradle bolts to. Do NOT connect to the cradle cross bolt. Drill a new hole into the plate that is welded to the Fiero body and connect it here using a nut and bolt.

I also connect at least one 8 or 10ga ground strap from the cylinder head or transmission case to the other cradle mounting plate that is welded to the Fiero body.

Make sure ALL connections have been sanded down to bare metal to remove paint, rust, corrosion, etc before bolting on your ground wires. Apply some dielectric grease to bare metal surfaces to prevent future rust and corrosion before making your final connections.

I DO NOT recommend running a ground cable all the way from the battery back to the engine block. This is unnecessary and can add extra resistance in the circuit if this is your only means of grounding the engine to the battery. If you do run such a wire, I recommend 2ga welding or automotive grade cable.

I also do not recommend grounding the engine cradle or the front k-member. It is unnecessary and unneeded.

Make sure all large ground cable connections made to the spaceframe are done so at thicker points of the metal (like welded on mounting pads or a few layers of sheet metal that have been welded together by the factory) and not just to single thin layer of sheet metal.

For the POS battery terminal connection, I run a 2 or 4ga cable directly from the POS terminal to the starter. I also like to run an 8 ga wire from the battery POS terminal (protected by the correct size and length fusible link) to the large, 12v + constant power wire feeding the radiator fan relay. I don't sever the radiator fan relay's power wire from the rest of the Fiero electrical system when I do this, I simply tie in an additional 12v + battery power feed directly from the battery to it. Doing this helps boost internal Fiero electrical system voltage by taking some of the load off of it put on it by the radiator fan when it turns on.

EDIT TO ADD: You still need to run a POS (+) wire from the starter terminal you connected the large battery cable to, up to the factory Fiero power distribution block near the C500 connector. I recommend using a 6ga wire for this.

-ryan

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[This message has been edited by Darth Fiero (edited 11-04-2014).]

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