blackrotary23

i know that when your alternator goes bad you pretty much have to jump the car every time you start it.

but what about runnability issues associated with a bad alternator? will a bad alternator cause my injectors not to fire properly along with the coil packs and all the electrical components under the hood?

farberio

iTrader: (7)

Get your alternator tested, its free and takes 10 mins to pull off.

blackrotary23

that really didnt answer my question.....

Vdub2002

low voltage can cause drivability issues... perhaps the better question is what problem you are having.

HAILERS2

A low voltage can effect the fuel pump flow and cause driveability problems........yes. If your having problems then get a meter and watch the meters output when your driving under load.

Either get some long meter leads and backprobe the power wire for the fuel pump at the fuel pump connector and or backprobe the power wires to the ECU on the ECU's small plug or???? backprobe the alt input wire to the igniton switch pigtail (the black wire in the two wire conenctor that has a black/white wire paird with a pure black wires.).

Watching the stk volt gauge wouldn't be a good way to do this.

The black wire coming right off the alt and feeding the ignition switch might be one of the best ways to monitor alt output while driving under load.

Either way you need to fix whatever is causing your difficult starting problems. Bad/old battery? Or some voltage draw that lasts all night pulling the batt down when you want to start in the morning. Who knows.

If your just having problem starting in the morning after it sits all night and you wonder why..........next time pull the BTN fuse in the engine bay before you put up for the night. Then reinstall it next morning and see if things are better or not. BTN feeds a battery bus in the interior fuse box and doing that would maybe eliminate a overnight draw from those components that are on the interior batt buss.

Or if you have a meter that can look at amperage (current)..........put it on amps and remove the negative cable from the batt. The meters positive lead to the neg cable and the negative meter lead to the battery negative posts and if the meters is on amps you should see maybe 11 milimaps max. If you see 1amp then something is pulling the batt down. Be sure to close the doors prior to doing this or you'll see the door light bulbs pulling power.

blackrotary23

well, here is my problem:
i have had my rx7 sitting for about a month now while waiting on all of my parts for the turbo conversion (ECU, wire harness, turbocharger, etc.)

i had a mixture of stock parts and TII parts trying to get the car to run. ecu was stock, airflow meter was stock, boost sensor was stock, wire harness was stock, and turbo had bad seals with no coolant lines.

i had to keep jumping the car every time i wanted to try to get it started because of the excessive cranking and tinkering around under the hood which kept draining the battery.

the battery is brand spanking new less than a month old and since i have put it in, it drains all the way down to 6 volts. i then attempt to jump it with my truck and i can get it started for about 2 minutes. after that, it stalls and wont restart. let the car sit for about 5-10 minutes and the battery is completely dead again.

farberio

iTrader: (7)

Maybe not, but it was quicker for me to answer that way. And if you just go get your alternator tested it will be quicker for you. Why are you wasting time?

89RedsunGTUs

iTrader: (1)

my alternator is bad and it keeps cutting the trailing coils and throwin on the CEL, and i get a bad bog, and lack of accelleration. i just want the FD alt to help support my Taurus fan madness lol

HAILERS2

Yeah you need to find what it is that is drawing the battery charge down.

Other than put a meter on the battery to see what the alternator is charging at I don't see how you can fix this problem. Next time its running put a meter on the batt and see what the voltage is. Should show approx 12v prior to start and 13-14 after starting.

I have something you might try. Next time it starts.........rev the engine over four grand a couple of times and then see if the thing will stay running without the jumper job. IF it does the meaning of that is..........the alt is NOT seeing the voltage off the L wire to excite the alternator. Reving high rpms will overcome that problem because the alt will self excite off the residual magnatizim internal to the rotor.

EDIT: Ah heck, you have a series five don't you. Well that might still work for you. Give it a try. Also make sure the METER fuse is good. IF the gauges work then the meter fuse is good and no sense looking to see if it's good.

HAILERS2

Sending the alt off to a store to have it tested won't help you at all if the alt isn't seeing the power on the L terminal or making sure the S termianl has batt voltage off the EGI fuse in the engine bay. EGI fuse is good 'cause the car starts, but whether it gets power to the alt is another question.

Try what I suggested in the post above. No meter required. IT either will keep runing after reving it high or it won't.

Got a digital meter? Key to ON and see if the small plug on the alt has batt voltage on both wires. Also while your there, make sure the large output terminal also has power with the key ON or key OFF. Should have it both times. After all that large sucker feeds the batt directly.

blackrotary23

well, instead of going through all the trouble of trying to see if the damn thing is bad, i think i am going to take off my buddies from his engine and try it on mine to see if it cures the problem.

arad99

iTrader: (2)

This is why some people don't like to give advice. Its not really "that much trouble".

HAILERS2

Just start the engine and rev it up high for a moment and see if it will now keep running. Less time than changing/swapping a alternator.

farberio

iTrader: (7)

I would think its more trouble to take his alternator, that he already took off, to the store to have it tested then to just wildly test other parts. But what do I know, maybe the OP lives 200 miles away from the nearest auto parts store?

farberio

iTrader: (7)

I would do this too, I have to do it on my FD alt to get it to excite.

jackhild59

iTrader: (7)

Your alternator can be tested at the store on the car.

esjoson1126

flickering lights on your dashboard (idiot lights) will indicate that your alternator is going bad or worst dead.

arad99

iTrader: (2)

If you are just wanting to know if your alt is bad - the longer you run the engine, the deader the battery will become. Even to the point that it will quit running entirely.

blackrotary23

its not the alternator. i tested it, and it is good. the battery is brand new, coils are firing and the engine is getting fuel. all parts under the hood are ALL tII parts. i checked all grounds and everything is grounding properly. i replaced the battery terminal connectors, spark plugs, wires. the main relay is working, the fuel pump is working, mass air flow is working or else the car wouldnt start when it finally decides to, tps is working, ecu is working and the metering oil pump is working. when it starts, it acts flooded for about 4 or 5 seconds then clears up. i have to keep my foot on the gas to keep it running for about 1 minute. when i let my foot off of the gas it will idle for about 5 seconds then die and wont start again then the battery goes dead and i need to jump it.

i dont know what else to do besides give up. i love this car and want to get it running and driving properly for the summer but it seems like the more money i put into it, then the less of a chance i have of getting it running. please.................i need some in depth advice. i have worked on these cars for over 8 years and have never ran into this problem before.

lunardeathgod

i dont want to steal your thread and this may help as well,

I know the fc alternator is weak, so is there a way you can increase the amount of power coming out of it?

blackrotary23

not really. unless you can get a ford alternator or use an s5 or FD alternator.....

bumpstart

what is the N number on the alt,, and what is the car ( s4 or s5 )
what shape plug fits into the back of the alt

i ask because there is fundamental differences in the way the s4 and the s5 alt work and they are wired differently

if you fit the wrong alt onto the wrong wiring then you will have a constant trickle and a battery boiling overcharge one way ( s5 alt on s4 wiring )
and if swapped the other way you will have an alt that overheats , undercharges and trickles ( s4 alt onto s5 wiring )

if you fit an s5 alt then the trigger wire MUST be from the battery
if you fit an s4 alt then the trigger wire MUST be from the ignition switch
ALSO
if you fit s5 alt to early s4 you must run another B+ wire to the fuse box or starter
( as the single wire is not rated for 70+ A )


no ifs, no buts,, no shortcuts straight to the B+ pins for trigger

read my recent posts and you will see diagrams if its all to hard to read

blackrotary23

i have the stock alternator that came on the engine. it is an N350 N/A alternator on an N/A chassis. i didnt have this problem until the whole turbo conversion build started. once i got the engine components together and tried to get it started, and tried to get it started, and tried to get it started, etc.....for about 100 times and it fired up probaby 5, then i started having this charge problem. i am thinking that the alternator is good, the battery is good, but since i was cranking it so much and never got anywhere, i think the starter is fried. it cranks kind of slow for the first 5 seconds, then it acts like the battery is dead. mind you, i have a brand new battery in it that i got today and the voltage is dropping down to little to nothing. i had the alternator tested and it came back 14.5 volts under load so i know it is good.

HAILERS2

An alternator that isn't putting out can cause problems due to lack of batt power/voltage.

Example: ME. A month or so ago I was reworking the headlight switch harness by installing a relay in the short harness to prevent a future problem. For reasons unknown to even me I also at the same time removed one of the CPU's plugs.

To make the story shorter.........I got hungry and decided to drive to the local TacoBell and get some dogfood in a shell. About a block away the car acted funny. By the time I was driving up to the speaker the car died. No restart. Battery would only give me a bit of a click, click for starting. And turning the headlights on resulted in dim lights.

Paid a guy 20 buckst to take me home to rip a batt out of another car......put in dead car and drove home after buying food.

Started the car up and checked the batt with a meter. Duh. Eleven volts running. Checked the alt small plug for voltage. Duh. None on the L wire. Shucks. Rev'd the engine up to four grand for a moment. Checked the batt voltage. Ureka. 13.5 vdc idling.

Light bulb went off. L is fed by the METER fuse to excite the alt. My gauges worked so it was good. Went and looked at the CPU to see if the white/black wire had voltage on it. Oopps. Plug off CPU resulting in no excitation to the alt resulting in my car barely making it to TacoBell and then dying.

IF during that short drive I had only just ONE TIME rev'd the engine high, the alt would have excited and the battery would have stayed charged and I'd have saved 20 bucks for a ride. And I guess if I'd have put the darn plug back on the CPU in the first place none of that would have happened.

Like I previously mentioned.........the alt may check out very good at the auto store, but when in the car if it does not see excitation voltage it ain't a gonna charge nothing much less the battery. Unless you get lucky and rev it high momentarily and it self excites itself.

Yep. Fuel injected cars don't run very long with the alt not charging the battery. On a low batt they stutter and die pretty quickly. Been there done that.

I don't see how you can get along without using a cheap digital meter of some sort. Fixes lots of problems or at least gives you a clue.

Installing a turbo EM harness on a non turbo series four car can result in the METER fuse blowing if memory serves 'cause there are differences in non turbo and Turbo EM harnesses. Not many but a couple.

Like BumpStart says in so many words...........what are you powering the small plug on your series five alt with? Stk series four wiring or??? Gauges working or not?