This is the story, i was getting pretty slow cranks recently, so i had my buddy check the volts while i cranked my car over and it dropped around 8.2 volts, so i assumed it was my battery and decided to relocate my battery at the same time. So i relocated the new battery behind my pass. Seat in the tub and i am still having slow cranking issues, now when i crank its around 8.7. It still starts fine but it floods easier now and id like to avoid this if possible. Any help is appreciated.

 

check positive cable to starter (and negative cable going under the oil filter bolted to the engine/bellhousing bolt) and battery terminals. look for corrosion and loose cables.

something ill let you read:

http://www.aa1car.com/library/voltage_drop_testing.htm

 

so you decided your battery was bad, purchased a new battery but then decided "**** it" and throw it in the storage bin? did you not at least check out the new battery first? or check to see if the fault is your wireing? you introduced more variables into your problem.

 

All our cars have a large voltage drop when the starter is engaged. I'm pretty sure mine drop into the 8-9 volt range when the starter is engaged. Normal to me. Starters require a lot of amps/voltage when turning an engine over.

Go have your friend monitor the voltage drop on his Yugo when starting. I bet it drops low also when the starter is engaged.

 

check your plugs for optimum spark..could be that you aren't getting enough spark to burn that fuel on start..like others have said above...check wires

 

Spark Plugs or Grounds are good places to start. Mine started to not start as quickly lately and I discovered a major engine ground and somehow become unattached (plus my plugs need to be done as well).

 

My battery was a 4 year old valuecrap battery so yea i assumed it was dead and replaced it. my plugs and wires are brand new, i just replaced them, and my old battery cables were all chewed up and had the wires exposed and some parts were rusty or corroeding, so that was my main reason for relocating it. I should check my engine ground, its probably overdue for replacement. I have a new battery, with new terminals, the ground is a 9 gage wire for about 8 inches to the bolt hole in the tub area, my positive is a 5 gage wire for about 8 inches into a 100amp circuit breaker and then the 5 gage countinues to the engine bay when it splits into another 9 gage for about 8 inches to the main fuse box, and another 9 gage wire for about a foot then i have it connected to the power wire that went to the starter.

 

Are those wire sizes too small for the distance the voltage has to travel? Or is it my fuse? Do i need a larger one, i heard 150amp was good, but i was working with what i already had. thanks for the replys.

 

8.7volts is a little low but ~9v during cranking is pretty common and normal.

relocating the battery was a bad idea in an effort to diagnosing a slow cranking issue, you introduced more resistance into the starter system with longer battery cables... the end result is actually less cranking volts, hence even slower cranking on a car with the same starter/battery.

if you want faster cranking the opposite is what you should have attemped to accomplish which is the shortest large gauge wiring to the starter as possible, the stock battery location is as close to the starter as you can physically move a full sized battery to. also the battery itself has an effect on cranking speeds, smaller utility batteries like some people put in that are made for watercraft for example, have less cold cranking amps and less reserve battery power than larger batteries do. the larger the battery is, generally, the faster and longer it will turn the starter. thicker battery cables will do the same also, by allowing current to flow more easily. smaller longer battery cables do the reverse, they bottleneck the current flow which results in slower cranking speeds and the cables themselves will start to get hot from it.

the negative terminal on the car should be as short as possible to a solid chassis ground and then you can "spider web" the ground cables to the rest of the car from there. i would run a ground cable directly to the starter from your main grounding point though, which will allow it a more direct path to the battery(also basically how the original negative battery cable was routed/designed). you basically can't have too many ground cables to various points on the car.

 

And thanks jjcobm, that site is very helpful and provided great info.

 

Thanks for all the info, my battery was dead, and then my slow cranking was because i i didnt have my wiring connected to the starter properly.

 

Im having these same issues with my rebuilt engine, i cannot seem to start her up ive tried 2 batteries, an interstate with 800cca and an optima redtop... the result however were the same, i got the starter tester and passed... it is a fresh rebuild and im wondering what the issue is i checked the ground cable and it seemed to get warm hot to the touch, while i cranked the car...its an s4 turbo II engine.... stock ecu 550 660 secondaries, ported turbo, i am using the NA wiring harness.

any suggestions???

im going to get the alternator tested tomorrow as well

 

the ground cable connects DIRECTLY TO the body mount of the starter, then to the STRUT TOWER ground point, and then DIRECTLY to the negative terminal on the battery. its getting hot because there is resistance in the line.

 

I hope that the New battery is a gel cell type battery(like Optima) and not a acid type battery.If you relocated the battery to the inside,the battery would be putting out fumes(if it was the old type).

 

thats the way its set up, ibjust ran an extra ground from the other side of the longest starter bolt to the strut tower. im stumped. i tried the battery off my other rx7 and it did the same... i got my alternator tested and its in great shape! how can i cldtart breaking the issue down? i checked the main harness ground and in going to take it off and scrape it clean for a better ground....

 

the battery is not relocated, its in its stock location its just acting up... there's a draw somewhere...i just checked the wiring to the battery and starter i even cleaned the main ground on the strut tower again and used a fresh ground bolt too. again its a TUrbo swapped GXL using the NA wiring harness with emissions deleted. on the ecu i Pulled 3 wires one from each plug, but i dont know if i the ones that I TRIED to pull where the correct ones for the swap. the ones i tried to pull are the power steering wire which is the knock sensor for the Turbo model (Pin 1R), I also pulled pin 2k(split air solenoid on NAs, but for the twin-scroll solenoid on turbos) and pin 3d(fuel pump resistor/relay on turbos, but is unused on manual NA)...

with that said the wires i pulled where:

The Light green wire with the black stripe off the biggest plug which is a 24 pin; then the Blue wire with a black stripe off the 18 pin harness; and finally the black wire with the red stripe off the smallest plug which is a 10pin( the injector plug)...

 

regardless of how its starting now, I feel your wiring could be heavier gauge
maybe im paranoid but I run a O gauge from the trunk to the engine compartment

 

Its probably your wiring cause i rewired mine and it cranks faster than ever before.
i used 4 gage from the driver side bin to a 150amp circuit breaker and to the starter and 4 gage from the starter to the fuse box.

 

i havent done anything special to the harness just extended the tps plug and sone of the tranny wiring cuz the plugs were too short... the car was sitting for two months tho but i highly doubt the harness got some corrosion inside???

 

i put a volt meter on the cables and seemed to be working fine.... i had some one turn the ignition on and start the car the see if there was some kind of a load and it seemed fine i had 12.15 volts on at the battery and 11.26-11.8 down at the wires... is that too much loss?

 

What do they measure while your cranking? mine is about 9-9.5 volts while cranking. And when i measure my battery its almost the same from it to the ends of the wires, just a slight drop.
your wires could be corroded.?? Im not sure.

 

i will do a test while cranking tonite and provide numbers then...thanks.

 

okay i bought a new optima, new starter, new terminals and added; the volts drop while cranking to 6-8 volts....and the car cranks a tad bit faster but yet has a bit of a lag still. i finally got it to fire up, it was on running at 3k rpm for about 30 seconds and it died, i was able to start it up again for 5 seconds then it died again....i checked the wiring everything looks fine,
im running 550/660cc injectors, walbro 255 and all stock turbo parts...i pulled the 1r pin off the ecu and thats it...need help guys i want to move this car out of my driveway!

 

Are you sure on this? 5 and 9 AWG are "theoretical" sizes, I've never seen them available commercially for sale. This would be a very expensive custom wire size.

Regardless, its too small.

 

same thing! now i think my optima.is about to die its wierd today when i cranked over the starter seemed to be engaging and rotationg the engine like an optima would except it only did it for the first two cranks. now its back to the same....